It’s easy to forget that the polarization trend in U.S. politics has led to strong differentiation within the parties themselves. We’ve seen, particularly since the emergence of the Tea Party movement, how the Republican Party has split. (The most recent manifestation of that divide: the inability of the Republican-led Senate to pass a  health-care overhaul, with the far-right and middle unable to agree.) During the 2016 election, we saw a split emerge on the left, too, with progressive Democrats increasingly expressing criticism of the more moderate wing of the party. (Think Bernie vs. Hillary.)

A new report from Pew Research puts a name to some of the factions within each party. On the left, there are the “solid liberals” and the “disaffected Dems.” On the right, the “market-skeptic Republicans” and the “core conservatives.” These groups are defined not by demographics but by beliefs, based on how they responded to a series of questions posed by Pew.

It’s worth focusing on two of the groups under the broader umbrella of the Republican Party: those “core conservatives” and a group that Pew calls “country-first conservatives.”

Demographically, both groups are predominantly white (as are most Republicans). The divide between the two is on income and education (which correlate). Country-first conservatives are less likely to have college degrees. This group overlaps more heavily with the “working-class whites” that gained so much attention over the 2016 campaign.

On questions of the U.S. role in the world, the country-first group is obvious. Three-quarters consider immigrants to be a burden to society; only 4 in 10 think that involvement in the global economy is good. About two-thirds think that openness to the rest of the world puts America’s identity at risk and believe that we should focus more on America’s problems.

Differences between “country first” conservatives and “core” conservatives are broader than just on nationalist views. Core conservatives are more likely to think the economic system is fair and that scientists contribute to society — and are less likely to think that homosexuality should be “discouraged.”

There are a lot more “core” conservatives than “country-first” conservatives in the Republican Party. (Pew actually aggregates Republicans and Republican-leaning independents into one larger group.) Among those who are more politically active, more than 40 percent of Republicans and leaners are categorized as “core.”

Assuming you hadn’t read the headline to this piece, you would likely assume that those “country-first” conservatives would view President Trump more favorably than the broader group of “core” conservatives. White working-class voters who agree with Trump’s nationalism? That seems like the definition of Trump’s core base of support.

If you read the headline, though, you know that this is not the case: 93 percent of “core” conservatives approve of Trump, 80 percent of them strongly. Among “country first” conservatives, 84 percent approve of Trump, 71 percent strongly. Those are good numbers — but they’re not as good.

“Country first” conservatives are less likely to say that they agree with Trump on all or most political issues — but they’re more likely to say that they approve of Trump’s conduct as president. (They’re also a lot less likely to say they have friends who are Democrats.)

There are two lessons to take from these data. The first is that Trump’s nationalist base thinks he’s being less successful than do more traditional conservatives. Part of this may simply be that Trump is now leading the Republican Party and has unavoidably become part of a system that this group seems more predisposed to dislike. It’s not clear from the data.

But the more important lesson is that Trump’s ongoing strength is a function of the sorts of Republican conservatives who’ve powered the party for the past decade. Trump’s overall approval ratings are low, but he’s been consistently viewed positively by members of his own party. This data from Pew suggests that it’s not because of a fervent core of usually disengaged working-class Republicans: It’s because more traditional Republican conservatives approve of the job that he’s doing.