ABC News' Michael Falcone reports:

Rick Santorum was warned more than a year before his decisive 2006 Senate re-election defeat that the controversial book he was writing would provide his opponents with damaging ammunition to use against him.

A review of the manuscript of Santorum's book, "It Takes A Family: Conservatism and the Common Good," conducted by political operatives several months before it was published found what the reviewers called "a fair amount of political opportunities," for Santorum's rivals.

The operatives identified nearly 30 "problematic excerpts" and suggested that some of them "might want to be edited or removed from the book."

One of those passages identified in the three-page memo written in 2005, a copy of which was obtained by ABC News, compared welfare programs to the Tuskegee medical experiments that began in the 1930s.

"The Tuskegee experiments denying black men treatment for syphilis were wrong and horrific, an example of the government using its power for evil," Santorum wrote. "But in terms of the sheer numbers of people, of all races, whose lives were destroyed, pre-1996 welfare was worse."

According to the memo, those lines appeared in a pre-publication manuscript of "It Takes A Family," but were removed from the final version, which first hit store shelves on July 4, 2005.

In the book, Santorum called the enactment of welfare programs before the 1996 reforms, "the greatest social policy debacle in American history."

John Brabender, who advised Santorum on his 2006 Senate race and is a strategist for his presidential campaign, did not deny the existence of the vetting document, but emphasized that "the only thing that is based on fact is the actual book, itself."

"Everybody who was only focused on winning the political campaign were giving us much advice on moving to the middle and moderating our message, but that's not something Rick Santorum would do," Brabender said in an interview with ABC News. "On the other hand, I'm sure Mitt Romney probably would have taken advice to move to the middle if he thought there was political gain because Romney seems to focus on the next election rather than what's right for America."

Santorum went on to lose his Senate race to then Pennsylvania State Treasurer Bob Casey that year by a more than 17-point margin. And the Democrats did use some of the more controversial ideas in the book to attack Santorum. On the campaign trail Casey criticized what he called his opponent's "harsh and intolerant" writings.

Since he launched his 2012 presidential bid, Santorum's 449-page book, which includes chapters on "The Meaning of Family,"  "Faith-Based Transformations," and "Culture: Ally or Adversary?" has been getting a second-look from newfound opponents in his own party and from the press.

Santorum's comments in the book about women in the workplace have drawn particular scrutiny.

"Sadly the propaganda campaign launched in the 1960s has taken root," Santorum wrote on page 95. "The radical feminists succeeded in undermining the traditional family and convincing women that professional accomplishments are the key to happiness."

In a February interview on ABC's "This Week" Santorum said that his wife, Karen, had actually co-written the chapter. "What I was calling for -very clearly calling for - is a treatment of, an affirmation of whatever decision women decide to make," Santorum said in the interview.

Whether or not his wife wrote it, the passage was one of the excerpts the operatives who scoured the book for potential areas of controversy, pinpointed.

"Sen. Santorum's opponents will probably focus on what they see as its divisive undertones," the reviewers wrote in the memo, which sources familiar with its writing said was given to Santorum and his aides before the book was published. "Sen. Santorum takes on long standing elements of the Democrat base and his opponents could use this book to rally their base."

The reviewers also highlighted an excerpt in which the former Pennsylvania senator compares pro-choice Americans to Nazi Germany - a passage that made the cut.

"One of the first phases of the (Nazi) German negative eugenics movement was active euthanasia of newborns and young children with congenital malformations and mental retardation," he wrote. "Prenatal diagnosis and selective abortion of fetuses with malformations or genetic disease can be considered an earlier phase of the same philosophy - namely, the elimination of lives not worth living."

In another case, it appears that Santorum tweaked a line in which he addresses economic differences between black and white Americans.

According to the memo, the original manuscript read: "Yes, there remains a very troubling economic disparity. But for the most part, this is not due to the continuing reality of discrimination."

However, the published book reads: "Still, there remains a very troubling economic disparity between whites and blacks. And this is really the result of a missing economic fundamental: business building and wealth creation."

But much of the book's content, including many of the passages indentified by those tasked with vetting it seven years ago, have become standard Santorum talking points - like this one:

"The truth is that liberal social policy has helped to dismantle the traditional family and failed the poor individuals they aimed to liberate," he wrote in the book's second chapter titled "The Liberal Vision: No-Fault Freedom."

It appears that in the vast majority of cases, Santorum did not take the reviewers' advice to tone-down the rhetoric, nor did he heed another warning.

"It is critical that this book not include an index," the operatives noted. "An index is an easy tool for lazier political operatives and reporters to use to dig up more controversial topics in this book."

The 2005 hard-cover printing of "It Takes A Family," includes a 13-page index.