Since he took office, President Trump’s weekly approval ratings as tracked by Gallup have consistently slipped lower. The first week, he was at a record low 45 percent approval. After week two, 43 percent. After week three, ending on Sunday, 41 percent.

We’ve noted before that this is largely a function of party. Trump is far more popular with Republicans than he is with Democrats or independents. His approval rating among Republicans is 46 points higher than his approval rating overall, while it’s 30 points lower among Democrats.

For his first three weeks, Obama saw a similar split, though in the other direction. His overall approval rating was substantially higher, with his approval rating from Democrats only 24 points higher than his approval overall.

As his two terms continued, though, Obama’s approval rating sank as his support from Republicans collapsed. By the end of his second term, over his last three weeks in office, the splits were the mirror image of where Trump began: Republicans 45 points lower than the overall average and Democrats 36 points above.

It’s important to note, though, that this split isn’t only seen in partisan identity.

In July, we noted the increasing overlap between race and partisanship. The Republican Party is mostly white; the Democratic Party is two-fifths nonwhite.

What that’s meant for presidential politics is that white voters are increasingly distant from the overall results of the election. Thanks in part to the fact that whites make up a smaller percentage of the electorate than in decades past, the difference in support for Republican and Democratic candidates from white people has increased dramatically since 1976.

That year, whites supported the Republican by 4 points more than the actual result and the Democrat by 2 points less. The peak was 2012, when whites preferred Mitt Romney by 12 points more than Americans did overall — and backed Obama by 12 points less. This year, thanks to increased third-party voting (also seen in 1992 and 1996), the figures were plus-11 and minus-11.

While the splits by race in presidential approval aren’t as stark as those for party, they’re still readily apparent. Here’s support for Trump by race.

And here are the first three weeks of Obama’s presidency.

Just as we saw in the partisan split, by the final three weeks of his presidency, support from white Americans had dropped while support from nonwhites had remained more stable.

Much of Trump’s campaign rhetoric was specifically aimed at white voters, a group that overlaps with his party’s base. Extricating how racial and partisan appeals are intertwined, though, may be increasingly difficult as racial polarization continues to mirror partisan polarization.