To assess how President Trump’s approval rating has been affected by the completion of special counsel Robert S. Mueller III's investigation, we looked at three approval measures. (Al Drago/Bloomberg News)

One would think that a purported “complete exoneration” by special counsel Robert S. Mueller III on the questions of collusion with Russia or obstruction of justice might give President Trump a bit of a political boost. After all, he has been claiming repeatedly since May 2017 that there was no collusion between Russia and his 2016 campaign and, again according to his claims, Mueller gave him a clean bill of health across the board. An expected effect, then? People suddenly viewing Trump more positively.

It hasn’t happened.

To assess how Trump’s approval rating has been affected by the end of Mueller’s investigation, we looked at three measures: FiveThirtyEight’s rolling estimate of Trump’s approval based on polling, RealClearPolitics’s polling average and the daily approval rating from Trump’s favored pollster, Rasmussen Reports.

Overall, the pattern shown is a familiar one: Trump’s approval rating hasn’t changed much. His approval rating rarely changes much, in fact, so, in the abstract, this isn’t a surprise. (Mueller’s report was submitted to Attorney General William P. Barr on March 22, and a letter from Barr detailing the conclusions of the inquiry was released on March 24.)

(Philip Bump/The Washington Post)

Approval tells only part of the story, though. It’s possible, for example, that some Americans moved from disapproval of Trump to not having an opinion, a more subtle shift in opinion. So let’s instead look at Trump’s net approval on each metric by day — the percentage approving of Trump minus those who disapprove.

Now, there’s a little more movement. The volatility in Rasmussen’s numbers is heightened (Trump goes from minus-nine to plus-one in two days?), but there does seem to be a larger jump in the RealClearPolitics average, too. (It’s worth noting that RealClearPolitics’s data includes Rasmussen’s polls, so a big increase in the latter will affect the former.)

(Philip Bump/The Washington Post)

The pattern is still a little unclear, so let’s look at averages. When we compare average values for the week before the Barr letter to the week following, we do see a small shift in Trump’s favor.

(Philip Bump/The Washington Post)

FiveThirtyEight went from a minus-12.8 to minus-11.9 points. Rasmussen had a similar improvement. The RealClearPolitics average went from minus-10.8 to minus-8.3, a 2.5-point improvement in Trump’s approval rating. It’s worth noting, though, that his net approval on that last index has been dropping for about a week.

Overall, these are subtle changes. But, again, why wouldn’t Trump see a boost from his claimed exoneration?

Well, as a Washington Post-Schar School poll found, most Americans don’t think Trump was exonerated. Only Republicans accept the president’s presentation of Mueller’s findings over what we know specifically from Barr’s letter, which includes a quote from Mueller’s report in which he says that Trump was not exonerated on the issue of obstruction of justice.

(Philip Bump/The Washington Post)

We haven’t seen Mueller’s full report, of course. But even before it was released to Barr, it wasn’t likely to do much to change people’s minds. A Fox News poll released last month, shortly before the Mueller investigation was completed, found that nearly three-quarters of Americans said that there was only a small chance at best that the report’s release would change their minds about Trump. Nearly half of Democrats said there was no chance that it would.

(Philip Bump/The Washington Post)

That we have only Barr’s brief overview of the report to work from leaves a lot of gray area in which existing views of Trump and his actions can continue to grow. It’s likely, in fact, that if Mueller’s full report is released, people’s views about Trump won’t change, given the broad disagreement that exists over the “collusion” question.

We return, then, to our perennial question: Could anything significantly move Trump’s approval numbers firmly in one direction or the other? The answer over the long term appears to be no.