This, from Mitt Romney adviser Ron Kaufman, is an oxymoron:

“Mitt will never be a great politician. But he might be a great leader and a great president.”

To be sure: I’m sure that what Kaufman is spinning is the notion that Romney’s low favorability ratings are somehow a plus — or at least irrelevant to his future presidency.

Putting that aside, however, and putting aside the other obvious point that getting people to like you is in fact important for a president, the main point is that being a good politician is what being a good president is all about. That, and not some sort of abstract “leadership” skills, is what made Franklin Roosevelt a great president and Jimmy Carter and George W. Bush terrible ones. You have to get the politics right, within and outside of the government.

Politicians aren’t great experts at the issues of the day; in fact, whether it’s deepwater drilling for oil or political revolution in the Arab world or the intricacies of monetary policy, presidents are often pressed to make choices on things they likely thought little about in their previous careers, or even during their campaigns. Even if they are experts, it’s not apt to help them all that much — it certainly helps to have at least a working understanding of things, but when it eventually comes down to it the president’s expertise is not going to be critical.

What presidents need, however, is political judgment. They need to know which advice to listen to, which usually means evaluating not just the person giving the advice but the incentives and political context surrounding that person. They need to know what objections mean: Is a Democratic senator objecting to an Obama policy doing it for show? To squeeze out a deal on an unrelated item? Or are they signaling that some important constituency has real problems with the policy? And not just in Congress: A similar set of questions have to be asked and answered in cases of bureaucratic resistance to presidential initiatives. When an agency chief says something can’t be done, is that just bureaucratic inertia, and the question is how much presidential effort will be needed to overcome inertia and whether it’s worth it? Is it a sign of constituency problems? Or is it a real issue of technical limitations?

How do presidents know how to answer those questions? How do they become experts at reading the clues that the political system is constantly giving them? How to respond? The answer, as Richard Neustadt told us long ago, is that presidents need first-rate political skills, including a well-developed sense of looking out for themselves — for after all, presidents are among those who suffer when wars go badly or cities are flooded.

Truth is, we have only the vaguest idea of how well good business skills translate over to politics; the skills are presumably not the same, but it’s hard to know exactly how applicable they might be. And with Romney, I have also only the vaguest idea of how well he demonstrated good political skills in his (very limited) experience in political office. I am, however, certain that one of the keys to whether he would be a good president or not is tied to how well-developed those skills are.

Unfortunately, political skills are often ignored by many in the press who are either more interested in image or issue positions. And even when the press does try, it’s awful hard to get a good sense of these things. We can see some of it in nomination politics, in the way that politicians deal with important people and groups within their party, but only some — there’s an overlap between campaigning and governing skills, but they’re not quite the same.

So if there’s one thing I want to know about Romney, as he enjoys his convention, it’s what we can know about his political skills. Because I do know one thing: You simply can’t be a good president if you’re a lousy politician.