Like another one-time New York mayor whose presidential ambitions were plagued by allegations of personal failings, Rudolph Giuliani hopes his record of public service will hoist him into the White House.

Last month, he created an exploratory committee to probe his chances of winning the Republican Party’s 2008 presidential nomination. That’s not going to be an easy task.

A recent Newsweek poll has Giuliani in a dead heat with New York Sen. Hillary Rodham Clinton in the 2008 contest. Clinton leads Arizona Sen. John McCain, who is expected to be Giuliani’s stiffest competition for the GOP nomination, by 7 percentage points.

But the poll, which tests his standing among a nationwide cross-section of voters, may not be a good indication of Giuliani’s ability to win the backing of the Republican Party’s right-wing base, if he decides to seek the presidential nomination.

The hurdle between Giuliani and the Oval Office is his tumultuous personal life. His first marriage, to a cousin, ended with an annulment after 14 years. His second marriage lasted 18 years and ended in divorce in 2002.

As her marriage to Giuliani fell apart, second wife Donna Hanover sought a court order to keep New York’s then-mayor from bringing his girlfriend into the official mayoral residence. Giuliani responded by stripping Hanover of her official duties as the city’s first lady. Giuliani and the alleged “other woman,” Judith Nathan, married the following year.

Presumably, Giuliani’s exploratory committee will assess just how much damage this sordid marital history would do to the presidential hopes of a man dubbed “America’s Mayor” after his high-profile leadership of New York City’s response to the 9/11 attacks. That damage could be considerable, given the influence of the religious right in GOP primaries.

But Giuliani might be encouraged by what happened to Grover Cleveland.

A Democrat and former mayor of Buffalo, N.Y., Cleveland’s 1884 White House campaign was threatened by the revelation that he had fathered a child out of wedlock 10 years earlier.

When news of his love child broke during the campaign, Republicans taunted Cleveland with the chant, “Ma, ma, where’s my pa?” He responded by admitting his personal failings and aggressively campaigning on a range of issues that resonated with voters.

After Cleveland won a narrow victory over Republican James Blaine, his supporters answered the GOP’s sarcastic refrain with: “Gone to the White House, ha, ha, ha.”

Giuliani has a long way to go before he can answer his detractors that way. He’s got to navigate a Republican presidential primary process dominated by voters who often place opposing gay marriage and abortion above the kind of national security and public policy issues that Giuliani might champion.

But if he can get GOP voters – especially those in the Bible Belt – to forgive his personal missteps and focus on his public service, Giuliani actually might transform the Republican Party. His moderate brand of politics – he’s liberal on social issues and conservative on fiscal and defense issues – could help stop the GOP from becoming the political instrument of those who would turn this nation into a theocracy.

Most of the Republican Party’s traditional ideals (small government, free markets, individual rights) have been plowed under by GOP leaders and activists committed more to the exercise of power than to the party’s traditional core beliefs.

Somewhere between the views of the party’s Nelson Rockefeller wing and its evangelical brigade is a GOP that can help erase this nation’s red-state-blue-state divide and give Rudolph Giuliani a good chance of following in the footsteps of Grover Cleveland.