The former vice president repeatedly invoked the Obama administration during an uneven performance in which he was confronted by his more progressive challengers. Here are six highlights from the debate and a look at how long each candidate spoke.

The details: The debate in Houston highlighted the central divide in the Democratic race: whether Mr. Biden and his incrementalism are more appealing than the structural overhaul promised by candidates like Bernie Sanders and Elizabeth Warren.

Reaction: Experts on the left and the right weighed in . We also fact-checked the candidates’ claims.

From Opinion: Our columnists and contributors ranked each candidate’s performance.

The Daily: Today’s episode is about the debate.

U.S. rolls back rule on clean water

The Trump administration on Thursday announced the repeal of an Obama-era regulation that had limited the chemicals that could be used near bodies of water.