There was a moment — a fleeting moment, but a moment nonetheless — in which President Trump was viewed more positively than negatively by the American public. While Trump never hit 50 percent approval in polling conducted by The Washington Post or ABC News, we did find at the outset of the coronavirus pandemic last year that, for the first time, more Americans approved of the job he was doing than disapproved.

Then everything went south.

In the most recent Post-ABC News poll, released Friday, disapproval of the job Trump is doing has matched the high set in mid-2018, with 60 percent of Americans viewing his job performance negatively. Only 38 percent of Americans approve of the job he’s doing, near the low of 36 percent recorded multiple times over his presidency.

More than half of Americans strongly disapprove of Trump’s job performance. Only about a quarter strongly approve of it.

Remarkably, this poll constitutes relatively good news for Trump. Pew Research Center released a poll of its own Friday, in which Trump’s approval rating is the lowest its poll had recorded. Only a dismal 29 percent of Americans approved of Trump’s job performance according to Pew, with two-thirds disapproving. From the spring, when Pew also found general improvement in Trump’s poll numbers, he’s seen his approval drop 16 points in Pew’s analysis.

Why? It’s simple: Republican support for Trump faded. In a Pew poll from last June, 77 percent of Republicans approved of the job he was doing. In the most recent poll, that figure was down to 60 percent.

This is really the only way Trump’s approval rating could have gotten lower. The story of Trump’s administration has been one of sharply polarized opinion. Democrats have long offered little or no support for the president, with independents generally echoing much of that skepticism. But Republicans held steady, consistently approving of what Trump was doing and, essentially, holding his overall approval rating steady in the way that two well-matched tug-of-war teams might keep the rope at a near standstill.

Put more simply, if Trump’s approval rating was going to fall, it was going to have to fall with Republicans. Pew’s data indicates that it did. In The Post’s polling, that effect isn’t as pronounced, with Trump’s approval dropping from 88 percent within his own party in October to 79 percent now. That’s low for Trump; he’s averaged 83 percent approval from his own party in Post-ABC polling since 2017. But it’s not that low.

There are nonetheless other indicators that Trump’s position with his party is softening. HuffPost’s Ariel Edwards-Levy noted polling conducted by YouGov for the Economist showing a big drop since December in the number of Republicans who say they strongly support the president. Both among members of his own party and even among those who say they voted for him last year, the percentage saying that they strongly support the job he’s doing has dropped more than 20 points and, for each group, is now under 50 percent.

This, too, was a necessary shift for Trump’s support to drop. It’s not generally the case that people simply flip their opinions of elected officials. It’s a continuum, with strong supporters becoming more indifferent supporters and then transitioning to ambivalence or opposition. That can happen slowly or quickly, but it’s generally the pattern that is followed.

So what happened to Trump? One factor, as we reported Monday, is probably the attempted insurrection at the Capitol last week.

In FiveThirtyEight’s average of polls, Trump’s average disapproval rating has spiked to its highest point since he took office. His average approval rating is not at its lowest point on record, but it’s headed south faster than a goose in autumn.

I apologize for that corny metaphor. But nevertheless:

That shift has not been slow. Since the mob of Trump supporters rioted at the Capitol, the shift in approval polls has been dramatic. It’s unlikely that this reflects Trump’s second impeachment, given the turnaround time on polling; instead, it’s likely that both the approval rating shift and the impeachment stem from perceptions of Trump’s culpability for that riot.

In the new Post-ABC poll, after all, 57 percent of Americans say they think Trump bears blame for the events at the Capitol. That includes 1 in 5 Republicans.

Last March, our poll showed that Trump’s net approval rating — the percentage saying they approved of Trump minus those who disapproved — was plus-2. By October, it was minus-10. In our new poll, he’s at minus-22, two points shy of his low in August 2018. The FiveThirtyEight average also has Trump at a net minus-22, near his low of minus-23.

But then we come back to the point we’ve made over and over again since Jan. 20, 2017: Trump nonetheless still enjoys the approval of between a third and 40 percent of Americans. If Trump’s approval rating is to fall even more, it would mean erosion from that most hardcore base of support. Past predictions that this base would erode have repeatedly proved incorrect, and one should be wary of predicting again that it will.

Attempted insurrection notwithstanding.