Rudy Giuliani wants voters to ignore his personal life and elect him president based on his record as New York mayor. Recent data indicate that may not be a winning strategy.

Republican voters think his personal life is relevant, are skeptical about a candidate – like him – who has been divorced more than once or has a strained relationship with his kids. They also don’t see a stint as a big city mayor as the best training to be president.

Of course, Giuliani remains the GOP front-runner. He leads national polls, although in the early voting states – Iowa, New Hampshire and South Carolina – he is behind in many surveys.

But his numbers have dropped, while former Sen. Fred Thompson of Tennessee and former Massachusetts Gov. Mitt Romney have gained. Sen. John McCain, after a dip, has stabilized his position.

Giuliani leads because 82 percent of voters in a recent New York Times/CBS poll say he has strong leadership qualities. But he is potentially vulnerable because his support for abortion rights, gay rights and gun control put him outside the GOP mainstream.

Moreover, in a nomination contest in which social conservatives carry great clout, his personal life is likely to be an issue.

Giuliani has been married three times, once to a second cousin. His second divorce was very messy, amid allegations of infidelity from his former wife that he has denied. Giuliani’s children have said they would not campaign for him. Their relationship, to put the best face on it, appears strained.

Giuliani uses that public perception he is a strong leader – perhaps the most important characteristic Americans seek in a president – at every opportunity. He tells voters that is what matters, not his personal life. He also steers the conversation toward his record as mayor, claiming he turned The Big Apple into a decent place to live.

But he may be surprised that voters nationally don’t necessarily see his service as New York mayor – which Gothamites like to say is the second toughest job in the country – as the right preparation for the Oval Office.

The New York Times/CBS national poll found less than half of voters thought being a big city mayor was the right kind of experience for becoming president. Four in five voters say being a governor or a U.S. senator is the right prior experience for being president.

On the stump, Giuliani tells voters his personal life should not be an issue.

“I’ve made mistakes. I’ve had a rocky road. I regret them. They are between me, God, my conscience and the people involved.”

Yet, clearly voters differ on that question.

That Times/CBS News poll last week found 64 percent of Republicans believe that presidential candidates should be judged on their personal life as well as their political record. If Giuliani gets by the primary he can take heart that only 48 percent of Democrats and 49 percent of independents feel that way. But, in most states, only Republicans can vote in GOP primaries.

Moreover, a recent Gallup Poll found 45 percent of voters – and 54 percent of Republicans – viewed a candidate’s strained relationship with adult children as an undesirable trait, a slightly larger number than who said that about candidates who changed their position on issues over time.

A Quinnipiac University poll of Florida voters this month added more fuel to that fire.

Voters were asked if they were more likely or less likely to vote for a candidate who had been divorced, or if it would not make a difference. Three percent said more likely, 11 percent, less likely. But when they were then asked how about a candidate who had been divorced more than once, the more likely figured stayed the same and the less likely total zoomed to 29 percent, including 31 percent of Republicans – a significant chunk of the GOP electorate.

Whether such numbers prove decisive, time will tell.

But they are a stark reminder that what may pass for common wisdom in Manhattan, N.Y, may not be the case in middle-American locations such as Manhattan, Kan.