A bunch of folks have argued that even if Mitt Romney lost last night, he did reassure voters by projecting a level-headedness that enabled him to pass the “commander in chief test.” I don’t know if that’s true — Romney seemed out of his depth in ways that might prove less than reassuring — but this misses something else about last night.

Specifically, the Obama team hopes Romney’s performance — his dissembling about the auto bailout in particular — provided them with new ammo to undermine voter confidence in Romney. That ammo, the Obama campaign hopes, will help them make their final case against Romney, i.e, that he is fundamentally untrustworthy and that Obama is the one who can be counted on to genuinely look out for you.

Obama, on the trail today in Dayton, Ohio, seized on Romney’s auto-bailout moment to broaden that case:

Last night, Governor Romney looked you right in the eye, looked me in the eye, and tried to pretend he never said “Let Detroit Go Bankrupt.”...But the people don’t forget. The people of Dayton don’t forget. The people of Ohio don’t forget.

If Mitt Romney had been President when the auto industry was on the verge of collapse, we might not have an American auto industry today. We’d be buying cars from China instead of selling cars to China. The auto industry supports one in eight Ohio jobs. It’s a source of pride to this state...I wasn’t about to let Detroit go bankrupt, or Toledo go bankrupt, or Lordstown go bankrupt. I bet on American workers. I bet on American manufacturing. I would do it again — because that bet has paid off for Ohio and for America in a big way.

So here’s the good news. If you’ve come down with a case of Romnesia, and can’t seem to remember the positions that you’ve taken, not just four years ago but four days ago; if you don’t remember the positions on your website; or the promises you’ve made during the six years you’ve been running for President, don’t worry: Obamacare covers pre-existing conditions. We can fix you up! There’s a cure!

Now, we joke about Governor Romney being all over the map. But it speaks to something important. It speaks of trust. There’s no more serious issue in a presidential campaign than trust. Trust matters.

The “Romnesia” label is not just some gag. It is part of an intense effort to undermine confidence in Romney’s character, integrity, and trustworthiness on a very basic gut level. And today, Obama added last night’s auto-bailout dissembling as another data point in the case.

Some polls have shown that Romney has made big strides in repairing his image and favorability problems as he’s closed the gap with Obama nationally. But in Ohio, large numbers still see Romney as uncaring about their needs and problems, and still think he can’t be trusted to help the middle class.

When it comes to this state, Obama strategists see the auto rescue as a stark black and white case that enables them to draw a sharp character contrast on one of the most basic questions voters ask themselves: In the end, who can you really trust to fight for you and count on to be on your side when it matters?

In this telling, Romney let Ohioans down when it really counted. He failed to support government help to bail out an industry that’s indispensable to Ohio at exactly the moment when Ohioans needed it most. And not only that, but Romney is now dissembling to their faces about it.

The storyline is simple: Obama came through for them; Romney let them down. And he doesn’t even have the character or integrity to admit it.

Expect a lot more of this in the final two weeks.