10. It would be very boring. People would stop paying attention to presidential politics. Campaigns are unique learning experiences, as Professor Gingrich certainly knows.

9. He doesn’t need his own plane. When you’re running to make a difference, running to energize people, attract them to politics and stimulate a real debate, all you need is a plane ticket to a debate.

8. Without Gingrich, Mitt Romney will veer to the middle faster than you can say Massachusetts. Every time he starts winning, that’s exactly what he does. Every time he starts losing, he remembers what party he’s in. For conservatives, Gingrich is the last best hope of keeping Romney on their side.

7. Gingrich brings out the best in Romney. Really. Until South Carolina, passive and predictable didn’t begin to describe it. The guy is finally going off script (Romney, I mean). He’s actually learning to fight. A scripted bore is not going to hold a candle to Barack Obama.

6. Gingrich brings out the worst in Romney. For example, his taxes. Imagine those coming out, say, next October. Disaster. And worse, Romney explaining that of course he deserves to pay lower taxes, because unlike the rest of us poor slobs, his income doesn’t come from working. The rule on bad news is always the sooner the better. Without an opponent, we’ll never know all the terrible things he must have done as governor of Massachusetts. Need I say the name that brings shivers to any Democrat old enough to remember? Willie Horton. Does Romney have one? Who knows?

5. Gingrich isn’t running for Senate. He doesn’t need the support of big-money establishment Republicans in the future. So what if they put pressure on him? They don’t have any power over him. And as for the world of talking heads, he’s already done that. The national stage commands more people than any talk-show studio. And if that’s where he wants to end up, sooner is not better.

4. No young person is going to go out and pound the pavement for Romney because he inspired them to believe in something, because they thought one person could make a difference, because they felt they were joining a political crusade. If anyone is going to do that, it’s Gingrich. Romney is Romney, Inc. No wonder he thinks corporations are people. He is one.

3. Maybe he’s right about the moon. Who knows? Unless he stays in, it will stay a laugh line.

2. What would “Saturday Night Live” do?

1. It would be such a disappointment to all of us Democrats if he got out. Here we are, united and rooting for Newt. And with friends like us, who needs enemies?