Conventions aren't that complicated, really. It's the beginning of the general election push, the formalization of a party's candidate and a chance for that candidate to make a pitch to a broad range of voters expected to come to the polls in November. It's four days of non-stop press attention, watched by millions of people.

And yet another poll released on Monday suggests that Donald Trump blew it.

We noted a poll from CBS released on Monday that showed Hillary Clinton taking a strong lead in the national presidential race. A few hours later, Gallup published data showing that Trump's convention was the first since the polling firm began tracking the question to find that a majority of people were less likely to vote for the candidate after watching it.

On Monday evening, a survey from CNN/ORC combined the two questions, looking at both the head-to-head match-up and voters' impressions of the conventions. If the goal of a convention is to expand a candidate's appeal -- which it is -- Trump's convention was a failure.

That wasn't immediately obvious. In the wake of the Republican convention, Donald Trump jumped ahead of Hillary Clinton in CNN/ORC's polling. (CBS showed both Trump and Clinton seeing 2-point improvement.) But after the Democratic convention, that lead had vanished -- and Trump ended up only a point higher than he was before the conventions began. Clinton landed at 52 percent.

You can see Trump's extremely brief spike in the polls more clearly in the RealClearPolitics polling average. A quick rise and a quick fall, leaving him about where he was.

Asked if the convention made them more or less likely to back the candidates, about half of respondents said the Democratic convention made them more likely to vote for Clinton, 10 points more than said it made them less likely to back her. By contrast, respondents said that the Republican convention made them less likely to back Trump by a 2-point margin. Voters also rated Clinton's convention speech as better than Trump's.

Our Greg Sargent asked Gallup who the people were that were less likely to back Trump after his convention, yielding an unsurprising answer: "Trump’s convention made white women, college educated whites, independents, and young voters less likely to vote for Trump."

The CNN/ORC poll found something similar. Three-in-5 nonwhite voters said they were less likely to back Trump after the Republican convention. Nearly half of the women polled did, too, while only 4-in-10 said they were more likely to. Forty-eight percent of whites who'd graduated from college said they were less likely to back Trump after seeing his convention -- though 56 percent of whites who hadn't graduated from college said they were more likely to.

In other words, the Trump convention appealed to people who already liked Trump and turned off people who didn't.

The change before and after the conventions among key demographic groups:

  • Whites, before the conventions: plus-13 for Trump. After: plus-14 for Trump.
  • Nonwhites, before: plus-48 for Clinton. After: plus-71 for Clinton.
  • Men, before: plus-3 for Trump. After: plus-7 for Trump.
  • Women, before: plus-14 for Clinton. After: plus-23 for Clinton.
  • White college graduates, before: plus-1 for Trump. After: plus-10 for Clinton.
  • White non-college graduates, before: plus-19 for Trump. After: plus-26 for Trump.

Notice, too, that Clinton now gets over 90 percent of the support from people who'd backed Bernie Sanders in the primaries. In a broader, four-way poll, that figure drops, but this is still an improvement from the 79 percent she got from that group before the conventions. Before the conventions, Clinton's support was mostly made up of people who were supporting her just because they opposed Trump. After, 58 percent of people who plan to vote for Clinton say they are doing that because they support her, versus 41 percent who simply want to oppose her opponent. (Clinton saw a 20-point swing on this metric. Trump moved 11 points, with 50 percent of those who plan to vote for him still saying they are doing it because they want to ensure Clinton loses.)

This is hardly game over. One hundred days left, and all that. Trump's problem, though, is that at some point he needs to convince more people to support him than support Hillary Clinton in enough states to get a majority of electoral votes. He can hypothetically do that with ads; he'd be able to do that at the debates. More polls later this week or month will probably show Clinton's post-convention bump fading, too. But it's still hard not to think that Trump's convention was a missed opportunity.