Mitt Romney's problem with evangelical Christian voters has been well documented.

But as the Republican presidential nomination fight heats up in Florida, a Mormon rite that leaves many Jews seething could prove awkward for the candidate in a state that's home to more Jewish people than any other besides New York and California.

The religious rite is proxy baptism for the dead. According to the Church of Jesus Christ of Latter-day Saints, or Mormon Church, these posthumous "blessings" are intended to "save" ancestors and others who weren't baptized in life or were baptized "without proper authority."

A Mormon may propose the baptism of another person posthumously. Church members have performed the ritual on Buddha, Catholic popes, 9/11 hijackers, William Shakespeare, Joan of Arc, Elvis Presley, President Obama's mother and even reportedly Jesus Christ. In 2002, the managing director of the Mormon's family and church history department told The New Yorker magazine that as many as 200 million dead people had been baptized as Mormons.

The names of most were listed in microfilm records at the church's Family History Library in Salt Lake City and in 4,500 branch research centers. The Mormon Church has spent millions of dollars microfilming, indexing and cataloging vital records from everywhere to enable its mission. Its genealogical treasure trove of 2 billion documents, open to anyone with the patience to troll through it, is the largest in the world.

In 1994, an Israeli genealogist researching her family in the Mormons' computerized International Genealogical Index made a startling discovery. Her grandfather, a religiously observant Jew killed in the Holocaust, had been posthumously baptized as a Mormon. Distraught, she alerted other Jewish genealogists who soon learned that some 380,000 Holocaust victims, including Anne Frank, had been baptized. Plus, Theodor Herzl, the founder of Zionism, David Ben-Gurion, Israel's first prime minister, and scientist Albert Einstein had received this treatment.

Negotiations between Mormon and Jewish leaders led to an agreement in 1995 to stop the posthumous baptism of all Jews, not just Holocaust victims, except in the case of direct ancestors of Mormons.

The church insists the deceased have "the right to choose" whether to accept Jesus Christ as their savior. But that hardly satisfied an outraged Jewish community. To them, the baptisms disparaged ancestors who were forced into ghettos, tortured in inquisitions, expelled from countries or murdered in pogroms and the Holocaust just because they were Jews.

"Baptizing is a very dirty word to many Jews," said Gary Mokotoff, a prominent Jewish genealogist who contacted church elders soon after the Israeli genealogist's discovery. "It reminds us of the persecution Jews had in the past where churches told Jews they had a choice: either convert to Christianity or be murdered."

"They tried to do something very difficult for Mormons to do, which was to stop the whole process of conversion," said Abraham Foxman, who lost 14 relatives in the Holocaust. As national director of the Jewish Anti-Defamation League, Foxman took part in the negotiations.

Still, Mokotoff told The Huffington Post, "overzealous Mormons" continued baptizing dead Jewish martyrs.

Renewed public outrage prompted more talks with Mormon leaders, who in 2010 agreed to a new, supposedly more ironclad pact that included changes to prevent inappropriate submissions of baptisms to the computer database records of Holocaust victims -- although not of all Jews. But Helen Radkey, an ex-Mormon whose research uncovered the continuation of Jewish baptisms that led to the second agreement, recently told Salt Lake City Weekly that violations of the pact continue.

Posthumous baptisms are among the practices that have made some voters squeamish about the prospect of a Mormon president.

In 2007, when Romney made his first run for the Republican nomination, NECN in Hartford, Conn., asked him about baptizing the dead. He said he is "not a cafeteria Mormon" and adheres to all tenets of his faith. But Romney, a former bishop and top church official in Boston, referred specific questions to religious leaders.

When Newsweek magazine asked Romney if he personally had performed posthumous baptisms on anyone, author Jonathan Darman wrote, "he looked slightly startled and answered, 'I have in my life, but I haven't recently.' The awareness of how odd this will sound to many Americans is what makes Romney hesitant to elaborate on the Mormon question."

There was no mention, and it is not known, whether the people that Romney personally baptized were Jewish.

Requests for comment by Romney campaign and the Mormon Church were not answered.

As a religious minority, Jews have been "somewhat more likely than Americans as a whole to say that a presidential candidate’s Mormon affiliation wouldn't make them less likely to support that candidate," said Kenneth Wald, a University of Florida political scientist who studies religion and elections. But, Wald added, other than the small minority of Orthodox Jews who lean Republican, most American Jews have "some concerns about what they perceive as the theopolitical nature of Mormonism." A recent Pew Forum on Religion & Public Life report stated, "Mormons are more conservative than the general public on a variety of political, social and moral issues."

Wald, whose grandparents died in the Holocaust, said, "Jews are understandably angered when another religious faith denies the legitimacy of Judaism by attempting conversion — and that is precisely what these retroactive baptisms do."

Mokotoff, the genealogist who credits the Mormon database for helping him trace his ancestors back to a small Polish village in 1727, said the controversy should be kept separate from the 2012 election. "Romney should be judged on his political views and political past," he said, "and not on the views of the president of his church."

But if Romney's rivals want to use the issue of proxy baptisms against him, they will do it "quietly under the radar lest Jews find themselves portrayed as intolerant toward a religious minority," Wald said.

Foxman doubts the issue will affect the outcome, "but everything is fair in politics so somebody's going to use it."

CORRECTION: While this article originally stated,

"Any Mormon may baptize any person posthumously," it has been corrected as follows: "A Mormon may propose the baptism of another person posthumously." CLARIFICATION: The Church of Jesus Christ of Latter-day Saints explains the practice of proxy baptisms as follows: "Because all who have lived on the earth have not had the opportunity to be baptized by proper authority during life on earth, baptisms may be performed by proxy, meaning a living person may be baptized in behalf of a deceased person. Baptisms for the dead are performed by Church members in temples throughout the world. People have occasionally wondered if the mortal remains of the deceased are somehow disturbed in this process; they are not. The person acting as a proxy uses only the name of the deceased. To prevent duplication the Church keeps a record of the deceased persons who have been baptized." As a BBC article explains, "Such baptisms can only be performed in special fonts in Mormon Temples." "Women act as proxies for women and men for men. There are witnesses present and a proper record is kept, although the ceremony does not make the person for whom the baptism is performed a Mormon."