I guess it bears repeating that Mitt Romney lost in 2012.

That makes the 2016 election a lot easier to figure out: Donald Trump has to win a few states that Romney didn't. It's as simple as that. If Trump can't do better than Romney, he will suffer the same fate.

And he is not doing better than Romney.

A number of polls put that into perspective. As we noted, seven polls of swing states from NBC, the Wall Street Journal and Marist released this week show Hillary Clinton with a lead. In six of those polls, her lead over Trump has increased since July.

The effect of the conventions isn't totally clear. The overall polling average in each state compiled by RealClearPolitics shows modest upticks in support in some states (Ohio, North Carolina), bigger increases in others (Colorado, Pennsylvania, Virginia) and no real change in Iowa.

We've only got detailed demographic data from three of the seven polls, which show a familiar pattern: Trump lost support overall, usually with bigger losses among voters with college degrees. Other than that, it's a bit all over the place, with changes often falling within the margins of error.

But here we go, getting bogged down in the details again. Of the 10 closest races in 2012, President Obama won nine of them. Right now, Donald Trump trails in all 10 — and in seven of the 10, he's doing worse than Romney did.

Trump's doing better in Iowa than Romney did, thanks in part to soft support from Democrats for Clinton in the state. He's also doing better in Nevada, but polling has been spotty there since the conventions.

But, ugh, mired in the details once again! As it stands, Donald Trump trails nationally, and he trails in each of the 10 closest states from 2012. In Georgia and Arizona, the two states Romney won that were the next closest, Trump is doing surprisingly poorly. In Arizona, which Romney won by nine points, Trump and Clinton are basically tied in the polling average. In Georgia, which Romney won by 7.8 points, Trump trails in the polling average, by 1.2 points.

I guess it also bears repeating that failing to win states Romney lost and losing states that Romney won would make things even worse for Trump. If you want to dig deep into the numbers to find a bright spot, go for it. The big picture is that Trump is trotting along on a slightly worse path than Mitt Romney walked in 2012 and that the numbers have been trending worse. Unless he changes course, it's pretty easy to predict where he'll end up.