Mitt Romney has started his pivot to the middle. Tom Edsall writes in The New York Times that Romney said something vaguely sympathetic about poor people last week, which of course one can’t do while seeking conservatives’ votes. The National Memo reports that Romney is attempting something similar on contraception. Watching this, it occurs to me: Romney benefits and will continue to benefit from the broadly shared perception that he’s a liar—that is, nearly everyone agrees that he isn’t really as conservative as he’s been acting for the past year. This is a strange and maybe unprecedented situation, and a pickle for the Obama campaign: How do they persuade centrists and independents that Romney is in fact dangerous?

We’ve all heard it a hundred times, even from some liberals: “Oh, I know Romney took extreme position X, but he just has to say those things to get nominated. He’s really more moderate than that deep down.” I think this is, among liberals anyway, a defense mechanism. That is, if you are liberal and you fear that Romney may beat Barack Obama, you want to tell yourself a story to help you deal with that expected day, and the story has to be about why that outcome won’t be so bad. So the story is: He’s really a moderate. He doesn’t seem loony. Once he gets in there, he’ll behave responsibly. That way, liberals can bear the thought of a Romney America and not start typing “Vancouver” into the Trulia search engine.

Centrists and independents appear, maybe, to be telling themselves similar stories. A new poll from the centrist Democratic group Third Way surveyed 1,000 independent voters in 12 swing states. Obama leads Romney among this group by 44 to 38 percent. But the catch came here: Asked to rate themselves from 1 to 10 on an ideological scale, the group collectively put itself at 5.2, slightly right of center. Meanwhile, respondents put Obama at 3.9 and Romney at 6.1—each of them equidistant (1.1 points) from the center. In other words, they said Obama is exactly as liberal as Romney is conservative, and they said they are a bit closer to Romney.

On paper it’s inconceivable that people could think either of these things. Obama has done some liberal things, for sure. But he’s taken many moderate and a few conservative positions. Project Voteview, a respected and valuable group, released results in February showing by their metrics that Obama was the least liberal Democratic president since World War II. And Romney hasn’t taken a single nonconservative position in the past year. (In fact, it's been since 2007.) Every time the right wing has said, “Jump!”, he’s said, “How high?” He has managed to attack both Rick Perry and Rick Santorum from the right (respectively, on immigration and being a “big-government” conservative). Whenever there was for a single instant a crack of daylight between him and the most extreme right-wing interest group on any given question—the Blunt amendment, conspicuously—he has rushed to seal that crevice as quickly as possible.

So why do people think he’s lying about all this? Because ... he’s from Massachusetts, I suppose. Because he doesn’t quite look and sound like the rest of them, he doesn’t have that same messianic glint in his eye or cadence in his speech. He can’t talk about religion, for wholly other reasons, and that probably helps him too. And mainly, of course, because he once held positions on many issues (abortion rights, the individual mandate) that are precisely the opposite of the ones he holds now.

But here’s a question. Why assume that the old moderate positions were the real ones and the new conservative ones are fake? Because he took the others first? So what? He simply said what he needed to say to win then, and he’s saying what he thinks he needs to say to win now. And here and there, we learn new things about those bygone days. Over the weekend, the Times reported that Romney and Bibi Netanyahu have been close buddies, almost soulmates, for 35 years. I don’t think he paraded that one around much while running against Ted Kennedy. So maybe he was lying then.

I always ask people this question: There was talk, after the Salt Lake Olympics from which he emerged a local hero, that he might run for office in Utah. He decided against it because he had lived in Massachusetts for a quarter-century and saw a clearer path there. So suppose he had run in Utah. Think he’d have been proabortion rights there, or passed a big health-care law? Obviously not. He’d have been whatever he had to be.

And this is my theory of Romney: He’s not conservative, but he’s not moderate either. Why people assume he must be one or the other is another puzzle, because there is a third choice, which is the correct one: none of the above. He’s everything, he’s nothing; he’s whatever he needs to be. And he has shown no political courage to buck his party’s establishment at any point in his career (pursuing health care in Massachusetts was hard, maybe, but not exactly an act of ideological daring). So, if he ever is president, he’ll be whatever the situation requires, which, given that he’ll be the head of a severely right-wing party, means that he’ll be pretty severely right wing.

Yet most Americans persist in thinking he’s “really” a moderate. What this reveals is that the voting public thinks Romney has been lying to us for the past year, or even five years. But here’s the exasperating thing: This is a lie that nets a huge plus for him. Far better a liar, people think, than a wingnut.

This presents a big challenge for the Obama team. Convincing Americans that Romney really is as right wing as he’s been acting is probably a very hard sell. Once people have an intuition in politics about a candidate, dislodging it is difficult work indeed. Convincing them of the Tomasky theory probably won’t work because while it’s good for punditry, it’s too subtle for electoral politics. But the Obama campaign obviously cannot concede that Romney is really a moderate.

Clearly, the Obama people have to choose door No. 1. They have to keep pumping the Ryan budget and Romney’s nativist immigration rhetoric, his backing of anticontraception measures and so on. He has, after all, no choice but to take these positions. The way to do it is not to try to say that Romney is personally really a right-wing lunatic, but that he is a man of elastic will who’ll do the bidding of the people who put him in office. Don’t make him a out to be one of the wingnuts, but tether him to them. That might work. And it has the virtue of being true.