A simplistic reading of the Book of Moses and the Book of Abraham together lends apparent justification for the priesthood ban.

It appears from various communication that Joseph Smith himself interpreted these verses in the straightforward manner, too. For instance, please consider in full his open letter to Oliver Cowdery in the Messenger and Advocate in April of 1836 (“but I can say, that the curse is not yet taken off the sons of Canaan”).

Moses 5:36-41 (emphasis added):

36 And now thou shalt be cursed from the earth which hath opened her mouth to receive thy brother’s blood from thy hand.

37 When thou tillest the ground it shall not henceforth yield unto thee her strength. A fugitive and a vagabond shalt thou be in the earth.

38 And Cain said unto the Lord: Satan tempted me because of my brother’s flocks. And I was wroth also; for his offering thou didst accept and not mine; my punishment is greater than I can bear.

39 Behold thou hast driven me out this day from the face of the Lord, and from thy face shall I be hid; and I shall be a fugitive and a vagabond in the earth; and it shall come to pass, that he that findeth me will slay me, because of mine iniquities, for these things are not hid from the Lord.

40 And I the Lord said unto him: Whosoever slayeth thee, vengeance shall be taken on him sevenfold. And I the Lord set a mark upon Cain, lest any finding him should kill him.

41 And Cain was shut out from the presence of the Lord, and with his wife and many of his brethren dwelt in the land of Nod, on the east of Eden.

Moses 7:22 (emphasis added):

And Enoch also beheld the residue of the people which were the sons of Adam; and they were a mixture of all the seed of Adam save it was the seed of Cain, for the seed of Cain were black, and had not place among them. (emphasis added)

Book of Abraham 1:20-27 (emphasis added) :

20 Behold, Potiphar’s Hill was in the land of Ur, of Chaldea. And the Lord broke down the altar of Elkenah, and of the gods of the land, and utterly destroyed them, and smote the priest that he died; and there was great mourning in Chaldea, and also in the court of Pharaoh; which Pharaoh signifies king by royal blood.

21 Now this king of Egypt was a descendant from the loins of Ham, and was a partaker of the blood of the Canaanites by birth.

22 From this descent sprang all the Egyptians, and thus the blood of the Canaanites was preserved in the land.

23 The land of Egypt being first discovered by a woman, who was the daughter of Ham, and the daughter of Egyptus, which in the Chaldean signifies Egypt, which signifies that which is forbidden;

24 When this woman discovered the land it was under water, who afterward settled her sons in it; and thus, from Ham, sprang that race which preserved the curse in the land.

25 Now the first government of Egypt was established by Pharaoh, the eldest son of Egyptus, the daughter of Ham, and it was after the manner of the government of Ham, which was patriarchal.

26 Pharaoh, being a righteous man, established his kingdom and judged his people wisely and justly all his days, seeking earnestly to imitate that order established by the fathers in the first generations, in the days of the first patriarchal reign, even in the reign of Adam, and also of Noah, his father, who blessed him with the blessings of the earth, and with the blessings of wisdom, but cursed him as pertaining to the Priesthood.

27 Now, Pharaoh being of that lineage by which he could not have the right of Priesthood, notwithstanding the Pharaohs would fain claim it from Noah, through Ham, therefore my father was led away by their idolatry;

Apologists (justifiably?) deconstruct the apparent connections in this manner:

[W]e see that the Book of Abraham says nothing about lineages set aside in the pre-existence, but only about distinguished individuals. The Book of Abraham is the only place, furthermore, that any scriptures speak of the priesthood being withheld from any lineage, but even then it is only the specific lineage of the pharaohs of Egypt, and there is no explanation as to why that lineage could not have the priesthood, or whether the proscription was temporary or permanent, or which other lineages, if any, especially in the modern world, would be covered by that proscription. At the same time, the passages in Genesis and Moses, for their part, do not refer to any priesthood proscription, and no color change occurs in either Cain or Ham, or even in Ham’s son Canaan, who, for some unexplained reason, was the one actually cursed! There is no description of the mark on Cain, except that the mark was supposed to protect him from vengeance. It’s true that in the seventh chapter of Moses, we learn that descendants of Cain became black, but not until the time of Enoch, six generations after Cain, and even then only in a vision of Enoch about an unspecified future time. There is no explanation for this blackness; it is not even clear that we are to take it literally.[

Note that in this composite apologetic scenario, the relevant sections from the Book of Abraham and Book of Moses are completely avoided (which is typical of apologetics on the topic):

Q : I hear that the Mormon Church is racist, or at least that many Mormons are. Anything to that rumor?

A : I guess most white people in America have grown up with some racist beliefs, and Mormons have had their share. However, national polling data for more than a decade have revealed that Mormons are actually less likely than other Americans, on average, to support racist ideas and policies.11

Q : But aren’t black people unwelcome in the Mormon Church, or subjected to some kind of second-class status?

A : Not for the past twenty-five years. It is true that from the middle of the nineteenth century until 1978 the few black people who joined the Church could not be given the priesthood.

Q : Why was that?

A : The reasons are not entirely clear, but the policy seems to have begun officially in 1852 with an announcement by Brigham Young, who was Church president at that time. He made that announcement as part of the deliberations in the Utah territorial legislature over the legal status of both blacks and Indians, and in particular whether slavery should be permitted in the territory.12

Q : So, was it permitted?

A : Yes, for about a decade.13

Q : That sounds pretty racist to me. How can you justify that?

A : I wouldn’t try to justify it. Slavery in America was a racist institution. Brigham Young himself did not actually want slavery in Utah, but he did believe that black people were not the social or intellectual equals of white people, and that slavery should be tolerated for Mormon slave-holders moving to Utah as long as it was tolerated elsewhere in the United States.

Q : Why would Brigham Young believe such things?

A : Because he was a nineteenth-century American, and hardly any white people of that time, North or South, believed in equality for blacks. Slavery was still an unsettled issue throughout the nation, with some even in the South opposed to it, and many even in the North who were willing to tolerate it. Brigham Young’s ideas were really right in the mainstream of American thinking at that time. They were very close to the ideas of other prominent Americans from Thomas Jefferson to Abraham Lincoln, who himself did not even free all slaves with his Emancipation Proclamation.14

Q : I thought most Americans of that time believed in God and in the Bible. Where was God in all this?

A : It is doubtful that God had anything to do with it. Many Americans of the time, including Brigham Young and most other Mormon leaders, believed that the scriptures justified the subordination of black people because they were descendants of Cain or of other biblical figures who had sinned egregiously. Latter-day Saints do not believe that God takes responsibility for the evil in the world, or that He condones the use of his name or of the scriptures to justify evil. Yet he has granted human beings their agency either to operate a society according to His principles or to pay the consequences. The Civil War and the racial strife since then have been the consequences of slavery.

Q : But don’t Mormons believe that their Church is led by prophets of God? How could prophets have permitted racist ideas and practices to become part of their religion?

A : Prophets are not perfect and don’t claim to be; nor do they always act as prophets in what they say and do.15 People in all ages, including those who become prophets, grow up without questioning much that is assumed by everyone else in their respective cultures, unless some experience motivates them to seek revelation on a given matter.

Q : Well, maybe so, but racism is such an obvious evil that I would think authentic prophets would have been more sensitive to it.

A : Why? It seems obvious to all of us now, but not to people who believed in Manifest Destiny, the White Man’s Burden, and “the only good Indian is a dead Indian.” Even the original apostles of Jesus assumed that non-Jews could not become Christians unless they first accepted Judaism and circumcision. The apostle Paul disputed that, but the idea persisted.16

Q : Did all the early Mormon leaders hold racist ideas?

A : Pretty much–like all other Americans. But there was a range of opinion. Not all of them embraced all of the racist ideas in the culture. For example, Joseph Smith, the founding prophet of the LDS Church, saw no reason to keep black people from holding the priesthood, even though he shared the conventional idea that they were descendants of Cain and Ham. We have no record that he ever sought a special revelation on the question; he just accepted blacks into the priesthood.17 He also believed that the innate inferiority of blacks so widely assumed at that time was as much a result of inferior environment and opportunity as of lineage.18

Q : So why didn’t Joseph Smith’s views on such matters prevail in the Mormon Church?

A : Joseph Smith was assassinated while still a young man, and well before the race question led to the Civil War. We can’t be sure whether his ideas would have changed later or how. We do know that his successor, Brigham Young, had somewhat different ideas, though not necessarily based on revelation; and he headed the Church for more than thirty years.

Q : Didn’t anyone question Young’s views during all that time or later?

A : All of Brigham Young’s successors tended to assume that he had had a good reason for withholding the priesthood from black members and had probably gotten the policy from Joseph Smith. A few black members questioned the policy a time or two, but when they did so, the Church leaders reconsidered and simply reiterated it. By the time the twentieth century arrived, no Church leaders were living who could remember when the policy had been otherwise.19 Meanwhile, the nation as a whole had become permeated with so-called Jim Crow laws restricting all kinds of privileges for blacks. In that environment, the Mormon restriction on priesthood seemed entirely natural.

Q : But other religious denominations were critical of such racial restrictions, weren’t they?

A : Eventually they were, but not until the age of civil rights in the 1960s. Prior to that time, only a minuscule number of blacks were ordained in any denomination–except, of course, in the so-called black denominations such as the AME and the predominantly black Baptist groups.

Q : But wasn’t the Mormon racial policy more pervasive and severe than in other religions?

A : Not really. In the Mormon case, the policy was simply more conspicuous because of the universal lay priesthood that Mormons extended to all men except blacks. In other churches, the racial restrictions were more subtle. Ordination to the ministry in all major denominations required access to the professional seminaries. Before the age of civil rights, the seminaries, like the schools of law and medicine, were the gatekeepers to these careers, and blacks were rarely admitted to any of the professional schools, including seminaries (except, again, in the black denominations). Most of today’s religious critics of the erstwhile Mormon racial restriction belong to denominations in which there were scarcely any more black ministers or priests than in the Mormon Church.20 Not many institutions in American society, including religious institutions, can be very proud of their historic treatment of black people.

Q : So you are saying that the Mormons were really no worse than others in their teachings and policies about black people?

A : That’s about right, small comfort though that might be in retrospect. National surveys comparing Mormons with others in racial attitudes indicate that Mormons in the West, at least, were close to the national averages in all such measures during the 1960s and 1970s–more conservative than some denominations but more liberal than others.21

Q : When did the Mormon Church finally change its policies about blacks?

A : 1978.

Q : That seems a little late. Didn’t most churches and other institutions drop all their racial restrictions a lot earlier than that?

A : Yes; generally a little earlier. But Church leaders had the matter under consideration for at least twenty years before 1978.22

Q : What took so long? Why couldn’t the prophet just change the policy?

A : Especially in such important matters as this one, a prophet or president in the LDS Church is not inclined to act alone. The president, his two counselors, and the twelve apostles are all considered “prophets, seers, and revelators,” and they usually act as a body when deciding on fundamental doctrines and policies. This process is by definition a conservative one, since it requires a relatively long period of discussion, deliberation, and prayer in order to reach a consensus–in order to feel that they have all been moved by the Holy Spirit toward the same decision. The prophets came close to consensus more than once across the years before they finally achieved it in 1978.23

Q : That seems like a very cumbersome process, which might actually constrain God in getting through to the prophet with a revelation. Why couldn’t God just speak to the president or prophet and tell him what to do?

A : Well, of course, God could do anything He wanted to do. In the Mormon tradition, however, the revelatory process normally (not necessarily always, but normally) begins with human initiative, whether that of a prophet or of any other individual seeking divine guidance. The individual formulates a question or proposal and takes that to God in prayer for divine confirmation. This was the pattern followed by Joseph Smith himself in what Mormons call “the Sacred Grove.” It is the pattern also in Mormon scriptures such as D&C 9 and Moroni 10:4-5. Mormon prophets do not sit around waiting for revelations. They typically take propositions to the Lord for confirmation, and these propositions are the products of a great deal of prayerful deliberation, both individually and collectively.

Q : So this is what finally happened in 1978?

A : Yes. President Spencer W. Kimball had anguished for some time over the restriction on black people, and he took a great deal of initiative in persuading his colleagues to make it a matter of the most earnest prayer and deliberation.24 In response to their collective efforts, he reported on June 8 that “the Lord (had) confirmed” (my italics) that the priesthood should be extended to all worthy male members (Official Declaration #2).

Q : Was President Kimball the first prophet to focus so intensely on the issue?

A : Not necessarily. Most of his predecessors said little or nothing about the matter, except for President David O. McKay (1951-1970). He was clearly deeply concerned about it even in the 1950s, when he visited several parts of the world with black populations, and even black Church members. One of his counselors, Hugh B. Brown, was also publicly anxious to see a change in Church policy. However, they were apparently never able to galvanize the consensus among the other apostles that might have changed the policy ten or fifteen years earlier.25

Q : Too bad. It would have looked a lot better for the Church if the change had come sooner.

A : Maybe, but not necessarily. During the 1960s, the Church was under a great deal of pressure over its racial restrictions from various national organizations and leaders. Indeed, I recall that period as a public relations nightmare for the Church. Yet if the Church had made the policy change then, the public relations outcome might have been anticlimactic, since the Church would have appeared to be caving in to political expediency, rather than maintaining its own prophetic and procedural integrity, even in the face of public criticism.26

Q : Well, anyway, now that the Church has dropped its earlier racist ideas and policies, is it attracting many black members?

A : Conversions in Africa are really quite startling, but of course racial conflict in the U.S. has never been especially salient to Africans. The growth of the Church among African Americans, however, has been much slower, largely because of the lingering racist heritage of the past, and the seeming inability of the Church to deal with this heritage candidly.27 Those black members and investigators who find it hard to look past all that have also found it hard to remain active in the Church. We have a lot yet to do.