1. They have held governorships.

Americans like governors. This country has a strong track record of sending governors to the White House. Members of Congress have not been as successful. Since FDR, we have only had three presidents who were neither governors nor vice presidents first: Eisenhower, Kennedy, and Obama. Eisenhower was a celebrated war hero, and JFK and Obama were young and fresh political dynamos, able rise above Washington stodginess.

Governors have character, and Americans like some level of panache in their presidents. They embody the unique character of their individual states. Pawlenty can work the gritty-but-kind image of Minnesotans, while Perry is able to draw on his deep well of Texas swagger -- though he must be careful not to swagger too hard. In contrast, Congress emanates the opposite of vigor and verve, placing candidates who come from there at a disadvantage.

2. They have the hope and change aura.

Americans also like hope and change -- and not just from Obama. Our political attention span is short and so is our patience for losers. We're always looking ahead toward next year's model. This is especially true when the economy is bad and we're tired of the way things have been going.

Pawlenty and Perry are new names to the national political scene. They have not run for president before, nor have they served in Congress. For this very reason, voters can attach aspirations of hope and change onto them more readily than to the other candidates. Romney and many of the others have already been tried on the national scene and failed.

3. They have actual economic records to run on.

Being a governor also means that you can tout your own executive accomplishments. Right now, voters care deeply about economic policy and fiscal records.

Pawlenty and Perry are at an advantage here because they have something to show for their time in office. The Cato Institute gave Pawlenty an "A" in fiscal responsibility. He cut spending and kept taxes low, while undertaking conservative healthcare reform. Perry too can tout his record of fiscal discipline. The effects of his tort reforms are noticeable. He can point to evidence that the Texas economy is performing comparatively well right now. Romney and many of the others cannot run on a record of low taxes and spending, and Romney of course will have to answer for his health care plan.

4. They are taking Iowa and New Hampshire seriously.

The factory tours and county fair appearances in both of these small states are tremendously important. Under the modern primary election system, Bill ClintonWilliam (Bill) Jefferson ClintonWith Ryan out, let’s blow up the process for selecting the next Speaker When Barbara Bush praised Bill Clinton, and Clinton praised the man she loved Meet the Democratic sleeper candidate gunning for Senate in Nebraska MORE is the only candidate to lose both Iowa and New Hampshire and still become president. Opting out of one or both of these states is a critical mistake.

Of all the candidates, Pawlenty is taking Iowa most seriously. He's also competing in New Hampshire. While it remains to be seen what Perry will do, there is evidence he is laying the groundwork for strong competition in both states as well. Meanwhile, reports are emerging that Romney and others are reigning in their efforts in at least one of these states. Ask Giuliani how that worked for him in 2008.

5. They can appeal to the base as well as the middle.

Voter turnout in primaries is pretty dismal. As a general rule, party loyalists are most likely to turn out. But part of their voting calculus is the candidate's ability to compete in the general election by appealing to the overall electorate.

Pawlenty and Perry are not just candidates of and for the base, as are Palin, Bachmann, and Paul. But the base also isn't questioning their conservative credentials, as they are for Romney, Huntsman, Giuliani, and even Gingrich.

To be sure, some candidates have overcome one or more of these factors and gone on to win the nomination -- John McCainJohn Sidney McCainRomney forced into GOP primary for Utah Senate nomination Trump considering pardon for boxing legend after call from Sylvester Stallone GOP poised to advance rules change to speed up Trump nominees MORE is a good example. But Pawlenty and Perry are the candidates who meet all five of these critical criteria and are therefore best positioned to surpass Romney.

Jill Abraham Hummer is Assistant Professor of Political Science at Wilson College. She is an expert on the presidency.