On this count, I see most of the major candidates on equal footing. Giuliani, McCain, Clinton, Obama, and Edwards can all be said to meet a basic threshold of electability, having led or been within the margin of error in most general election polls. The only one who consistently trails is Mitt Romney, and we wouldn't know until March 2008 (if he were the nominee) if this was because of his low name identification or something else. He doesn't get zeroed out just yet, but he does get docked half a point.

"The 14 Year Rule." In 2003, Jonathan Rauch posited the "14 year rule" -- the maximum amount of time it takes from when you're first elected to public office to a spot on a winning Presidential ticket. Call it a politician's "sell-by" date. It almost never goes wrong as a predictor of Presidential victory.

Kennedy, Reagan, and Clinton all were elected precisely 14 years after winning their first major office. Others like the current President Bush were even fresher; more experienced hands like Nixon and Bush 41 attained the Vice Presidency within the 14-year window. Romney, Obama, and Edwards are safely inside their sell-by dates. Rudy Giuliani (first elected in 1993) and Hillary Clinton fall right in a gray area -- Giuliani because municipal elections fall on odd-numbered years, Hillary because she has been a constant presence for 16 years, though she has been in elected office for eight. John McCain would nearly double the 14 Year Rule, with 26 years in Congress.

Bonus Points. Incumbents win most of the time, and people who wouldn't otherwise be considered Presidential frontrunners attain that status because of a little thing called the Vice Presidency. This year, we extend that definition to a former First Lady who is widely considered the Democratic frontrunner because of her past national prominence. She gets a half-point bonus. Why just half? Though past national leadership may get you into a general election, it traditionally hasn't trumped factors like executive experience in an open seat election.

The final score: Giuliani 4.5, Obama 4, Romney 3.5, Edwards 3, McCain 2.5, Clinton 2.5. How do past Presidential winners stack up? Bush arguably swept all 5, Clinton had 4 (minus authenticity), Reagan had 4 (minus electability). George H.W. Bush was arguably in the 2-3 range.

Though these may be dismissed as the ravings of a committed Giuliani supporter, I do believe this goes a long way towards explaining the current national momentum of both Giuliani and Obama. And yes, Obama's presence near the top of the list is surprising. Whether someone so inexperienced in public life can get elected hasn't been tested, but past experience shows that Americans may prefer fresher faces when it comes to the Presidency.

Am I wrong? And if so, how would you score both current and past candidates? Weigh in in the comments.