Robert S. Mueller III in 2007. (J. Pat Carter/Associated Press)

President Trump, officially under investigation for possible obstruction of justice, is back with self-pitying tweets. (“They made up a phony collusion with the Russians story, found zero proof, so now they go for obstruction of justice on the phony story. Nice.”) But regardless of whether there is proof of collusion, Trump has left a trail of evidence of obstruction that even Inspector Clouseau could follow. And make no mistake, special counsel Robert S. Mueller III and his A-team of investigators and prosecutors are no fools.

A besieged, whiny president is not a popular president. Consider the latest Associated Press-NORC Center for Public Affairs Research poll: “A clear majority of Americans believe President Donald Trump has tried to interfere with the investigation into Russia’s alleged election meddling and possible Trump campaign collusion, a new poll shows. Just one in five support his decision to oust James Comey from the FBI.”

The poll has even more troubling results for Trump:

Two-thirds of Americans, or 65 percent, think Trump doesn’t have much respect for the country’s democratic institutions and traditions or has none at all. Just a third of Americans, or 34 percent, thinks he has a great deal or even a fair amount of respect for them.

Overall, 64 percent disapprove and just 35 percent approve of his job performance.

Trump was unpopular among Americans overall even as he was elected president, but the poll shows that even many Republicans have doubts. Nearly a third of Republicans and independents who lean toward the Republican party think Trump has little to no respect for the country’s democratic institutions, and a quarter disapprove of the job he’s doing as president.

Nine in 10 Democrats and 6 in 10 independents say the same.

Moreover, the assumption that if he could just get back to his agenda, his favorability ratings would bounce back doesn’t hold up. Also, Republicans are beginning to defect from the Trump camp. “Among whites without a college education, who voted overwhelmingly in favor of Trump last year, 50 percent say they approve of Trump, down slightly from 58 percent in March. Health care remains Trump’s worst issue in the poll, with 66 percent disapproving of his handling of the issue. Even 33 percent of Republicans disapprove of his handling of the issue.” His numbers on climate change (64 percent disapprove), foreign policy (63 percent disapprove), immigration (60 percent disapprove) and the economy (55 percent disapprove) underscore that Republicans risk their own political future if they rubber-stamp Trump’s policy choices.

In short, the rationale for Republicans’ continued defense of Trump erodes by the day. The public at large thinks Trump’s conduct has been improper, and Americans are not so entranced with Trump’s agenda that they feel desperate to preserve his presidency. Lawmakers in deep-red environs still must contend with constituents who remain devoted to Trump, but beyond those areas, political self-interest dictates that they defend the work of the special counsel, take their oversight responsibilities seriously and push back on the president’s unpopular positions on both domestic and foreign policy. (As to the latter, we already saw a 97-2 Senate vote for Russia sanctions that pointedly restricts Trump’s ability to unilaterally roll back sanctions, evidence that his party no longer agrees with him or trusts him when it comes to the Russia threat.)

We have long thought that a disastrous outcome in the 2018 midterm elections would be a prerequisite for congressional Republicans to abandon Trump. However, given the speed of the special counsel’s work and the growing conviction among voters that the president and his initiatives are unworthy of support, it’s not inconceivable that support for Trump in the GOP-led House and Senate will disintegrate before then.