In the wake of President Obama's victories in 2008 and 2012, a new genre of triumphalist punditry emerged, based on the assumption that Democratic domination of presidential politics was inevitable.

Republicans would never win again, we were told. Their midterm election victories of 2010 and 2014 could be written off as the product of a smaller, whiter electorate whose days are numbered.

Then again, what if the reason for all of the recent Democratic successes was just its stellar candidate, Obama himself? What if there is a good reason Democrats have failed in midterms and off-year elections, when he did not appear at the top of the ballot, to capitalize on their supposed dominance?

If that's the case, life after Obama could look ugly for Democrats.

Quinnipiac University this week released polls of three swing states that were critical in both of Obama's electoral victories, Colorado, Iowa, and Virginia. In all three, Hillary Clinton trails Republicans Marco Rubio, Jeb Bush and Scott Walker. Take your pick, she loses. For that matter, so do her other Democratic rivals, Vice President Joe Biden and Vermont Senator Bernie Sanders.

What's more, Clinton, the prohibitive favorite for the Democratic nomination at this point, already enjoys near-universal name recognition in all those states. In contrast to her competitors, voters have made their mind up about her, and her numbers don't look good — 21 points net-negative favorability in Colorado, 23 net-negative in Iowa, and 9 in Virginia. Majorities have a negative perception of the former first lady.

None of this means Clinton cannot win. But it is a reminder that Obama's victories represent just one political moment. His campaign assembled a winning coalition in part because his candidacy inspired certain groups (the young, blacks and Hispanics especially) to turn out in unusually high numbers and, even more importantly, deliver him unusually large and historic margins of victory.

There is no reason to assume that any non-Obama Democrat can replicate this feat, which means future elections could look like 2004 just as easily as they could look like 2008.

There is an important lesson in these polls for conservatives as well. It has become the rage for a small yet significant minority of GOP primary voters to tell pollsters they are supporting Donald Trump, the bouffant billionaire who until five minutes ago was a big Democrat and took liberal positions, and who still is largely ignorant about political issues.

Perhaps these Republican voters are just trolling the pollsters. But these new state polls should serve as a reminder of just how absurd it would be to throw away a promising election cycle like this one, in which several top-shelf conservative candidates with at least some actual electoral appeal will also be on the ballot.

Set aside his ignorant bluster, the fact that he isn't a conservative, and his recent slurs against Mexicans and prisoners of war. Trump also has the worst net-negative favorability of anyone running in those three states, except that New Jersey Gov. Chris Christie is slightly less popular in Colorado (30 points net-negative to Trump's 27). A Trump nomination would guarantee a Clinton presidency, and a funeral for all conservative priorities in governance.