‘Looking for a reason to attack’: How Trump seized on a Fox News broadcast to go after Cummings

President Trump was already seething about Rep. Elijah E. Cummings.

He was frustrated that the oversight committee Cummings (D-Md.) chairs authorized a subpoena last week that could sweep up emails from his daughter and son-in-law. He was annoyed that Cummings stood alongside Democratic leaders discussing the possibility of impeachment following testimony by the former special counsel.

And he was particularly incensed when the longtime Democratic lawmaker lambasted Trump’s acting head of Homeland Security over reports from the border of “a child is sitting in their own feces, can’t...