President Trump on the South Lawn of the White House on Aug. 17. (Andrew Harnik/AP)
Opinion writer

The latest Quinnipiac poll finds:

As a candidate, [President] Trump frequently claimed he would hire “the best people.”  Few Americans agree that this promise has panned out a year and a half into his term. Just 30% say Trump does hire the best people, while a clear majority of 58% say he does not. Another 7% volunteer that the quality of his hiring choices have been mixed.  While most Republicans (67%) say that Trump does hire the best people, a sizable minority of his fellow partisans either disagree (18%) or give a mixed response (11%). On the other hand, nearly all Democrats (93%) say that Trump does not hire the best people.

You’d think it would be difficult to argue they are the “best” people when Trump turns around to fire them at regular intervals, but his cult followers won’t be deterred. At any rate, the confidence in current staff is low (42 percent very or somewhat confident, while 55 percent are either not too or not at all confident).

Well, if the president didn’t hire the best people, he at least passed a popular tax bill, right? Not so much. The poll finds that “37% of the public approve of the tax reform plan passed by Congress last year while a larger 45% disapprove.” This is worse for the Trump tax plan than results earlier this year. No wonder Republicans are not bringing it up much on the campaign trail.

Trump is right about one thing — Omarosa Manigault Newman isn’t helping matters. Fifty-four percent of those polled said Trump did not show good judgment by hiring her, while 17 percent disagreed. (While Manigault Newman is under water in her favorability ratings,  Trump has only partially succeeded in smearing her. Fifty-five percent have no opinion of her at this point.)

With Paul Manafort’s jury still deliberating, a plurality of voters polled (42 percent) said prosecutors in the case were motivated by a combination of facts and political motives; 29 percent said just by the facts, and 16 percent said it’s all politics. Those percentages likely will change when the verdict comes in.

But Trump should be wary of another data point: “Just under half of the public believes the Manafort charges suggest there may be widespread illegal activity among White House staff (45%) while nearly as many do not believe that this case necessarily suggests there is similar activity by White House staff (38%). These results include the expected partisan split, with 68% of Democrats saying the Manafort case suggests widespread illegal activity and 65% of Republicans saying it does not.” It is noteworthy that while 35 percent or so of Republicans say Manafort’s case is indicative of widespread conduct, nearly 90 percent of them approve of the job Trump is doing. I guess he — or his staff — really could shoot someone on Fifth Avenue and retain GOP support.

There are a few takeaways here.

First, Trump doesn’t seem able to get above the low 40s in favorability. That’s a problem for Republicans in the midterms. Last year, Charlie Cook wrote: “History tells us that the president’s party almost always loses House seats, which has happened in 35 out of the 38 midterm elections (92 percent) since the end of the Civil War. . . . When a president has job-approval ratings of 50 percent or higher, his party tends to keep its losses fairly low. But in six of the seven midterm elections since 1966, when presidential approval ratings hovered below 50 percent, his party has lost two dozen or more seats in the House, giving the opposition party a majority the next year.”

Second, while Republicans are very resistant to the idea that Trump might be responsible for his own White House, larger numbers are willing to recognize the people around him may not be honest or competent. In this regard, facts do seem to matter. With Manigault Newman running rampant, and Paul Manafort facing a mound of evidence, the sense that the administration is less than pristine is taking hold. Democrats have begun to stress corruption as a campaign angle, and the polling may explain why.

Finally, things may get much worse for Trump and his circle of cronies. The Associated Press reports, “Michael Cohen, President Donald Trump’s former personal lawyer, could be charged before the end of the month with bank fraud in his dealings with the taxi industry and with committing other financial crimes, two people familiar with the federal probe said Monday. The people confirmed reports that federal prosecutors in Manhattan were considering charging Cohen after months of speculation over a case that has been a distraction for the White House with the midterm elections approaching.” Regardless of the outcome of the current Manafort case, another trial — one related to his representation of a pro-Russian party in Ukraine — awaits. And Donald Trump Jr. purportedly has not been questioned by the special counsel. (If he is a target, he wouldn’t be brought in for questioning.)

In short, Trump — as we’ve seen from his latest tweetstorm — is incapable of curbing his outbursts. He’s not going to change, but the facts might get worse before the midterms. That could convert a wave into a wipeout.