President Trump's support among independent voters has eroded since he took office. Though he still clings to a loyal base of supporters, his overall disapproval among Americans has reached record highs, according to a new NPR/PBS NewsHour/Marist poll.

Just 37 percent of Americans approve of the job Trump is doing just over five months into his tenure, while 51 percent disapprove. Forty percent of those polled strongly disapprove of Trump's performance, twice the 20 percent who strongly approved.

The most pronounced swing seen in the poll was among independents. Over the past four months, their approval of the president has dissipated. In February, 40 percent of independents said they approved of the job Trump was doing, with 51 percent disapproving. Four months later in June, just 31 percent say they approve of the president with 59 percent of independents disapproving — a 17-point net-negative drop.

Despite almost full employment nationwide, independents are particularly dissatisfied with Trump on the economy. That's likely driving much of their overall disapproval. Just 31 percent of independents say they have confidence in Trump's ability to improve the U.S. economy, while 49 percent doubt he can do so. Just three months ago, 44 percent thought Trump could turn around the economy, while 38 percent didn't — a whiplash-worthy 24-point swing.

Lee Miringoff, the director of the Marist College Institute for Public Opinion, said that the scope of the shift over the past few months among independents should cause "alarm bells to go off" at the White House.

"Independents were certainly willing to give Trump the benefit of the doubt when he entered office," Miringoff said, "but on issues like the direction of the country and the economy, they've really soured on him. It's hard for someone like him to make a second impression. Independents have come to the conclusion that what you see is what you get."

The good news for Trump is that his base hasn't abandoned him even as he's faced mounting investigations. Eighty percent of Republicans still approve of the job he's doing, including 91 percent who identify as strong Republicans. Trump has an 89 percent approval rating among those who voted for him last November. He has a 65 percent approval rating among white evangelical Christians, though almost a quarter disapprove of the job he's doing.

Still, there are some warning signs for the president among some of his key demographic groups. Only 52 percent of white, non-college-educated Americans approve of the job he's doing, though just 37 percent disapprove. And that is higher than most other subgroups. More worrisome for the president, among older Americans, 60 and up, he's underwater — 47 percent disapprove, while 43 percent approve.

Overall, Americans' outlook under Trump is dismal. Almost double say the country is on the wrong track as those who think it's on the right track, 61 percent to 31 percent, a gap that's nearly doubled since February.

More people say they feel worse off — 40 percent — since Trump took office, than better off — 34 percent. There's a deep partisan divide on that question, of course — 73 percent of Republicans say they're better off, while 67 percent of Democrats say the opposite. Among independents, far more — 44 percent — say they're worse off, compared with just 27 percent who say they're better off.

Americans also think Trump has hurt the country on the global stage. Fifty-eight percent say the president has weakened the United States' position abroad, while 34 percent say he has strengthened it.

In addition, by a 24-point margin, Americans believe former President Barack Obama was, by far, a more effective leader in comparison to Trump, 58 percent to 34 percent. Among independents, there's an even more pronounced 36-point difference, 65 percent to 29 percent.

A narrow plurality do think Trump is keeping his campaign promises (48 percent who do and 45 percent who don't), but most people disagree with some of the president's recent decisions. Fifty-three percent of those surveyed said they opposed Trump pulling out of the Paris climate accord earlier this month, while just 30 percent supported it.

Just over half of Americans also think the Supreme Court should rule against Trump's travel ban, which would curtail the entry of people from six Muslim-majority countries, while 43 percent say the high court should rule in the president's favor and allow him to proceed with one of his key campaign promises. A slim majority of independents (52 percent) also think the court should strike down the ban.

There's a cloud of suspicion that hangs over the president as well, with mounting questions about his business ties that are only compounded by his continued refusals to release his tax returns. More than six-in-10 Americans say they believe Trump has either done something illegal (33 percent) or unethical but not illegal (28 percent). Just 31 percent say they believe he's done nothing wrong.

One place where Trump is losing GOP support is over his Twitter habit. Sixty-nine percent of Americans say Trump's use of Twitter is "reckless and distracting," while only 21 percent say it's "effective and informative." Even among Republicans, only a narrow plurality (43 percent) say the president's use of Twitter is positive, while 42 percent agree it's reckless and distracting.

And while Americans have a sour view of President Trump, their opinion of Congress — both Democrats and Republicans — is no better. Congressional Republicans have a 33 point net-negative approval rating (28 to 61 percent) while congressional Democrats are not much better with a 27 point net-negative approval (30 to 57 percent).

"Nobody is benefiting in Washington from what is going on," Miringoff said.

Looking ahead to the 2018 midterms, registered voters say they're more likely to vote for a Democratic member of Congress over a Republican one by a 10-point margin, 48 percent to 38 percent.

But, with a gerrymandered congressional map that benefits the GOP, that double-digit advantage is less imposing than it may seem and may not be enough to help Democrats win back the House.

What's more, as they learned in last week's special-election loss in a Georgia House race, making the election too much about Trump isn't necessarily a silver bullet, either.

The NPR/PBS NewsHour/Marist poll surveyed 1,205 adults from June 21-25 contacted by live interviewers using a mix of landline and mobile numbers. There is a 2.8 percentage points margin of error. A sub-sample of 995 registered voters were also surveyed, with a 3.1 percentage points margin of error.