Conventional wisdom suggests that in the end, vice-presidential picks really don’t make a difference. Ultimately, voters’ choices are driven by the choice at the top of the ticket.

But in a race that could come down to a single swing state and less than a million votes’ difference, the right No. 2 choice could absolutely have an impact on the outcome in November.

Presidential candidates are in control of just four opportunities to substantially affect public opinion and move poll numbers: the announcement and rollout of the candidacy; the debates; the convention nomination speech; and the selection of a vice president.

And for those who think the VP pick is just about politics, it bears noting that in the last 40 years, four of the 10 presidents also have served as vice president. Two were elevated by election, one following an assassination, and another by a resignation.

So, all things considered, it’s damn big deal.

So, allow me to join the punditry parlor game and offer some handicapping on Mitt Romney’s likely choice. The emerging consensus, which seems pretty solid, is that Romney’s vice-presidential-selection process will be incredibly buttoned up, methodical, comprehensive, and ultimately—here is the key—safe.

Unlike four years ago, when John McCain faced stiff anti-Republican winds and needed to throw deep in an effort to erase a huge Democratic advantage, this year the race is a jump ball. So there’s no need for risk. It’s not Romney’s style, anyway.

Certainly, when you’re the challenger and the race is pretty close to dead even six months out, the operative VP imperative is “first, do no harm.” Thus, while analysts will be consumed with this topic for the next three months, don’t expect any real surprises.

Let’s just eliminate the drama and suspense right now. Romney is going to pick Rob Portman. He is as safe a bet as they come. Plenty of experience as a congressman, senator, budget director, and cabinet member. Perfect family. No apparent skeletons in the closet. And he’s from Ohio—the most important swing state. He’s a loyal soldier. Good political instincts and judgment. Solid character and a genuinely nice guy. Almost zero liabilities, which is really what Team Romney wants. Game. Set. Match.

Portman is likely to get the nod, but here’s the rest of the top-10 field who will likely sneak off to undisclosed locations for interviews sometime in the next couple months.

2. Chris Christie: probably too interesting. But seems to be have great chemistry with the nominee. Helps with independents.

3. Bobby Jindal: conservatives love him. Brings some ethnicity to the ticket. And no one understands health care better.

4. Marco Rubio: checks so many boxes. Florida. Conservative. Tea Party. Hispanic. Young. But not the slam-dunk with Mexican-Americans many might assume.

5. Paul Ryan: the controversial budget master. Real answers. Romney’s for Ryan plan, anyway, so why not go all in?

6. Bob McDonnell: if not for some contentious women’s issues, being from key swing state Virginia, he’d be higher on the list.

7. Mitch Daniels: even more boring than Portman, so really safe. And, therefore, a safe bet. Common sense. Straight talker. Good on budget.

8. Tim Pawlenty: if the goal is to put voters to sleep and not create a ripple, he’s the guy.

9. Susana Martinez: key-swing-state governor. Hispanic. Woman. But untested. And, therefore, unlikely.

10. Jeb Bush: everyone thinks he’d actually be the best pick. And no one thinks he’s going to get it. But he should.

Long shots: Nikki Haley, Kelly Ayotte, John Thune.