There are three built-in “moments” in a general election campaign: Running mate selection, the convention, and the debates. So yes, choosing a running mate is important. So who will Romney select? Here’s a quick and easy guide to the pros and cons of his most likely choices.

1. Tim Pawlenty – The former governor of Minnesota was an early endorser of Romney (after scrapping his own campaign), and Romney seems comfortable with him. This would be a relatively safe, if boring, pick.

2. Rob Portman – The Ohio senator would be a safe and “serious” pick, but also a boring choice. There is little reason to believe he would automatically “deliver” Ohio, and his tenure as George W. Bush’s White House budget director would certainly be a double-edged sword.

3. Bobby Jindal – The Louisiana governor is popular, smart and experienced. On the down side, he talks too fast — and is too wonky for his own good. He likes to get in the weeds. Still, as I Tweeted the other day, nobody exciting is safer and nobody safer is more exciting.

4. Paul Ryan – If Romney wants someone who would excite the base — while simultaneously picking someone serious who has a lot of experience — Ryan could be an interesting pick. Ryan is only a House member, which probably hurts him (though he is budget chairman), and he is also clearly associated with efforts to reign in entitlement spending (this would, of course, open the door for Democratic demagoguery.)

5. Chris Christie – The New Jersey governor was an early endorser of Romney, and has impressed by taking on the unions in his state. If conservatives worry Romney won’t be tough enough on the campaign — or once in office — having Christie by his side might assuage those concerns. But my guess is that Romney is going to be very cautious and adopt a “do no harm strategy” when it comes to picking a running mate. And the fact that Christie has only served as governor for a few years, I think, makes him an unlikely selection.

6. Marco Rubio – There are a lot of good reasons why Sen. Rubio is an attractive candidate, but I’ll give you just two reasons for consideration: Electorally, I think he delivers Florida. And in terms of governing, I think he can actually articulate a conservative vision in a persuasive manner. But again, my guess is Romney will not pick a running mate who has only been in the U.S. senate for a couple years.

Considering Mitt Romney’s apparent risk aversion, the ghost of Sarah Palin looms especially large over this selection. Despite the fact that she likely helped John McCain, the perception that she hurt him has become conventional wisdom. As a consequence, it becomes much less likely that Romney will select anyone who could in any way be accused of being inexperienced.

Of course, one could argue that being a senator from Florida (who was previously Speaker of the Florida House) or Governor of New Jersey is quite different from being governor of Alaska. But my guess is the perception that Palin hurt McCain has poisoned the well for the more interesting, if risky, selections.

Lastly, I have probably left some favorite names off the list. Maybe Romney will surprise us and pick former Gov. Mike Huckabee or Sen. Kelly Ayotte or, Condi Rice, Rep. Cathy McMorris Rodgers? But I doubt it. My guess is there is  90 percent chance he picks one of the top four on my list…