Insinuating that people of color are foreigners, the president used a trope broadly viewed as racist when he tweeted on Sunday morning that the Democratic women, only one of whom was born outside the United States and all of whom are American citizens, “originally came from countries whose governments are a complete and total catastrophe.”

The silence of Republican leaders appeared to suggest either that they agreed with the views expressed by their standard-bearer or that he has so effectively consolidated his control over their party that they have grown disinclined to voice dissent.

Another possibility, that Republicans do not see the Twitter-induced presidential fracas as relevant to them, would seem tenuous as the controversy in this case engulfed their own colleagues in Congress. One move that still reliably provokes intraparty backlash is Trump’s crusade against John McCain, the late Republican senator from Arizona.