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 take a shower.”…

Trump, one senior White House official said, “was looking for a reason to attack.”

For Trump, that reason came shortly after 6 a.m. Saturday morning, when Kimberly Klacik, a Baltimore area Republican who is black, appeared on “Fox & Friends” talking about video footage she had taken depicting Cummings’s district as overrun by trash and blight…

Several conservative leaders on education and urban issues encouraged Trump on Monday to follow the Twitter battle with Cummings with a visit to Baltimore that is centered on policy rather than personality. White House aides have privately discussed sending Trump to the city, but no final decisions have been made, said two people with knowledge of the discussions.