What did Donald Trump do today?

He complained that his connection to the Russian attack on his election was hurting his popularity.

Trump ended yesterday's national day of mourning for the late President Bush with a triumphant tweet celebrating his "50% approval rating," according to a Rasmussen poll. Today, he pivoted back to attacking the federal investigation into his connection with the Russian attack on the 2016 election, complaining that if not for the Mueller probe, his "approval rating would be at 75%."

Trump almost exclusively cites Rasmussen polls when he wants to claim he is popular (or at least not deeply unpopular), and for good reason: they are much, much friendlier to Republicans than other polling outfits.

For example, Rasmussen's final pre-Election Day poll predicted that Republicans would win the total popular vote by a margin of 1%. In the election itself, Democrats won by 8.6%.

According to every other national polling outfit, Trump's approval rating is much lower. The widely respected fivethirtyeight.com weighted poll average has him at 42.1% approval (52.3% disapproval), which makes him the single most unpopular president at this point in his term since scientific polling began under the Truman administration.

That having been said, there is some truth to Trump's claim. The Mueller investigation is investigating, among other things:

• the extent of Russia's efforts to elect Trump and otherwise illegally disrupt the election;
• which Russian individuals committed crimes as a result of that attack;
• whether Trump's National Security Advisor Michael Flynn lied to federal investigators about his ties to Russia;
• whether Trump's firing of FBI Director James Comey was an attempt to obstruct justice by protecting Flynn;
• whether other Trump campaign officials and political allies (including Carter Page, Roger Stone, Jerome Corsi, George Papadopoulous, Paul Manafort, Jefferson Sessions, and Rick Gates) lied to Congress or federal authorities about their Russian contacts;
• whether Donald Trump knew about a meeting in which Trump's son and son-in-law sought to obtain blackmail material against Hillary Clinton from an agent of the Russian government;
• whether the Russian government exerted financial influence over Trump;
• how many campaign finance violations occurred as a result of the Trump campaign's solicitation of blackmail material;
• whether the Russian government had compromising information about Trump;
• whether the Trump campaign coordinated with the Russian "fake news" disinformation campaigns on social media;
• what additional previously unknown connections existed between the Trump campaign and agents of the Russian government, and
• which, if any, of Trump's attempts to influence witnesses or hinder Mueller's investigation itself are criminal acts or warrant an impeachment recommendation.

Trump is correct that he would almost certainly be more popular if these things had not happened—or if there were no one investigating them.

Why should I care about this?

• A president's popularity less important than the integrity of American democracy.