Following a weak response to violence from white supremacists over the weekend, Donald Trump's approval ratings fell Monday to the lowest point in his presidency. According to Gallup tracking, 61 percent disapprove of the job Trump is doing as president while his approval fell to only 34 percent, a low never once reached in Gallup tracking by either Barack Obama or Bill Clinton.

I know, I know: the polls are supposedly missing Trump's supporters, showing an artificially low job approval number. Trump's allies have a credible case when they gripe about the polls, given the shock of last November's election. Most voters – including three in four Republicans – don't think you can trust the polls very much, and I don't necessarily blame them.

But even if I concede the "real" number of Trump approvers could be higher, it doesn't explain the shift in the number over time . The trend line is what matters, and the trend line has been bad for the president in the last two months. Either people are changing their minds about Trump, or increasing numbers of his supporters are deciding it is too embarrassing to admit they support him. Neither is a particularly good position to be in.

So, how low can he go? After looking at a variety of polls, it seems about one in four voters is with him no matter what. I've noticed this number not just in recent job approval tracking but on a host of questions about the president's temperament and tweeting, the two items most likely to get a thumbs-down from reluctant Republicans who have stuck with him.

If you've reached August 2017 and still think Trump is presidential and that you like his tweeting and trust what his administration has to say, it's fair to wonder if you would disapprove if he shot someone on Fifth Avenue, as Trump has famously joked he could do without losing his supporters. And, indeed, a consistent quarter of the public as of late has been in "ride-or-die" mode with Trump, unwavering even as criticisms and failures of his presidency mount.

Take job approval, the most basic indicator of how a nation views its leader. In CNN's latest poll and in Morning Consult/Politico's tracking polls from last week, both polls show 24 percent of voters strongly approve of the job President Trump is doing.

Or trust in whether his administration is honest: The CNN poll shows only 24 percent of Americans say they trust all or most of what they hear from the White House.

Long have critics suggested Trump would be best off deleting the Twitter app from his phone, and in ABC's mid-July poll, only 24 percent of respondents said they approved of Trump's use of Twitter.

And on whether Trump is presidential? Only 24 percent in ABC's poll said they thought Trump had acted in a way that is fitting and proper for a president.

Monmouth University released a new poll on Tuesday with a quarter of respondents saying that not only do they approve of Trump, but "they cannot see Trump doing anything that would make them disapprove of him."

It's interesting to look at other poll questions over the last year or two on issues where Trump has been clear and vocal and where we find about a quarter of Americans falling into his camp. In June, Gallup found a quarter of Americans think that immigration is a bad thing for the country. Last summer, Pew found a quarter of Americans think that former President Barack Obama had made race relations worse during his presidency, and this spring, Pew found just over a quarter of Americans held negative views toward Muslims.

While none of these polls offer a breakout that says what percentage of those respondents would consider themselves Trump supporters, it would not be surprising at all if there was significant overlap between those groups. Indeed, political scientist John Sides finds that in analyzing data about voter preferences in the last election, "the attitudes that became more strongly related to the vote in 2016 [were] attitudes about immigration, feelings toward black people and feelings toward Muslims."

The data – on issues and on Trump himself — keep pointing back to "one-in-four" as the true size of Trump's base. It is around one in four who like the tweeting, like the insults, the things other people say are mean or unproductive behavior.

If Trump's job approval erodes to down to this level, that would almost certainly spell electoral doom for Republicans. On the eve of the Pelosi wipe-out of GOP House control in 2006, former President George W. Bush had an approval rating that looked a lot like Trump's does now, to say nothing of how bad things could get if they fall further.

But one-quarter of the 160 million registered voters in America is still 40 million people. That's not enough to win re-election, but it's enough to pack a lot of arenas donning red MAGA hats — and that may be good enough for Trump's tastes.

Kristen Soltis Anderson is a columnist for the Washington Examiner and author of "The Selfie Vote."