For years, a cadre of left-leaning, political-science-aligned or -curious pundits have offered a simple diagnosis of what ails American politics: the Grand Old Party.

That’s not an oversimplification of the stance. In 2012, for example, my colleague Norm Ornstein and Tom Mann wrote a Washington Post column titled, “Let’s just say it: The Republicans are the problem.” The critique hinged on what they call asymmetric polarization—yes, politics is more polarized than any time in recent memory, but that is not (the argument goes) because both parties have become more extreme. Nor is it a factor of partisan sorting, the idea that while both parties used to have liberal and conservative wings, the Democrats are now a uniformly liberal party and the Republicans a uniformly conservative one. Rather, the Democratic Party moved slightly left, but the Republican Party has moved far right.

But what if the asymmetric trend is no longer so asymmetric? Recent polling from Pew finds, as one might expect, that not only are parties becoming ideologically homogeneous, but so are people. Two decades ago, or even one decade ago, most Americans had a mix of conservative and liberal views. That’s increasingly not the case. Today, 97 percent of Democrats are more liberal than the median Republican—an even more extreme concentration (by a hair) than across the aisle, where 95 percent of Republicans are more conservative than the median Democrat.

At Commentary, Noah Rothman is annoyed that the Pew results aren’t getting more attention. They are newsworthy, but they might have gotten more attention if not for the squall of other huge stories over the last week. The major culprit for those stories is also the likeliest reason for the partisan shifts: Donald J. Trump.

Digging into Pew’s numbers, something notable emerges. Starting around 2015, views among Democrats and Democratic-leaning voters (I’ll just refer to this group as Democrats from here on out) tend to change sharply. For example, here are Democrats’ view on immigrants, perhaps Trump’s No. 1 target on the stump:

My colleague Peter Beinart has written about how the Democratic Party’s views on immigration went from heterogeneous to peculiarly single-mindedly in favor, but this chart illustrates just how dramatically the trend accelerated from 2015 on, when Trump came out slurring Mexicans as rapists and criminals. Democrats reacted to Trump’s rhetoric by sprinting in the opposite direction.

Or how about the idea that discrimination holds African Americans back? The discourse around “white supremacy” has gotten louder in recent years, along with a focus on police violence against people of color, but Trump was also busy with racial dogwhistles. Look at the sharp curve in Democratic opinions:

How about the value of diplomacy? It had risen somewhat since 1994 overall, but from 2015 to present, the trend gets steeper, just as Trump dismissed diplomatic methods:

These are merely the most drastic examples, but there are several other cases where Democratic sentiment turns dramatically around 2015.

These results don’t really falsify the argument that Ornstein, Mann, and other pursued. For one thing, not everything they identified as a problem hinged on polarization per se; norms are also an essential part of the equation, and there’s no Democratic equivalent of Donald Trump. The asymmetric polarizers also focused most of their attention not on the general public but on the way that legislators voted, and this data is about the general populace.

Yet there is, naturally, a connection between the voters and their representatives, as Mann and Ornstein pointed out about the GOP in 2012. One question to track is whether Democratic legislators now start behaving as Republicans have in Congress. Predictions of a “Democratic Tea Party” or an irredentist faction equivalent to the House Freedom Caucus have so far come to naught. One reason is that Democratic voters tend to value compromise more per se, and the Pew poll suggests that is one thing that hasn’t changed. Seven in 10 Democrats say they like elected officials who can reach deals, while a slim majority of Republicans prefer ones who stick to their positions.

Predicting the durability and effects of the changed positions of so many Democrats is a job for people with political-science degrees and the stomach to make bold predictions. Even without peering into the future, the Pew results craft a vivid image. Trump has radically changed what the Republican Party stands for, but he’s had a powerful impact on the Democratic Party’s identity too.