Over this past weekend, President Donald Trump put U.S. Rep. Elijah Cummings and his Baltimore district in his crosshairs, tweeting at him 17 times in a racially-charged salvo of alternately bigoted, hostile and inaccurate insults that commenced at 7:14 a.m. on Saturday and concluded at 6:49 a.m. on Monday.

Baltimore and its neighboring areas, the president allowed, were a "very dangerous & filthy place" and a "rat and rodent infested mess" where "no human being would want to live." Cummings was "incompetent" and a "brutal bully" responsible for Baltimore's problems, a "racist" who "spends all of his time trying to hurt innocent people."

As he has done before, Trump also retweeted the musings of a far-right British pundit who is a self-described racist to make his case against Cummings.

A broad, diverse swath of Baltimore residents and supporters responded to Trump by coming to Cummings' and their city's defense, acknowledging that Baltimore had myriad problems, including crime and poverty, but was hardly the noxious monolith the president was slagging. #WeAreBaltimore became a ubiquitous hashtag and a rallying cry on social media.

Perhaps the most poignant and powerful voice in all of that was a CNN anchor, Victor Blackwell, who was born in Baltimore and noted during a pointed, emotional broadcast on Saturday that Trump frequently uses the words "infested" and "infestation" when describing the homes or countries of people of color.

"Donald Trump has tweeted more than 43,000 times. He's insulted thousands of people, many different types of people. But when he tweets about infestation, it's about black and brown people," Blackwell said. "There are challenges, no doubt. But people are proud of their community. I don't want to sound self-righteous, but people get up and go to work there. They care for their families there. They love their children, who pledge allegiance to the flag just like people who live in districts of congressmen who support you, sir. They are Americans, too."

Mick Mulvaney, the president's acting chief of staff, sat for an interview with Fox News on Sunday and said there was nothing racist about Trump's comments.

"If I had poverty in my district like they have in Baltimore," Mulvaney said, "I'd get fired." (Mulvaney's old South Carolina district does have poverty rates like Baltimore's — as do many of the rural, red state districts that Trump avoids criticizing).

U.S. Sen. Rick Scott, a Florida Republican, went on "Meet the Press" and simply pandered to Trump when the news show's host, Chuck Todd, asked him about the tweets aimed at Cummings.

"I didn't do the tweets Chuck, I can't talk about why he did what he did," Scott said. "But I am disappointed in people like Congressman Cummings who are attacking border patrol agents."

And while the president was comfortable attacking a politician for Baltimore's woes, he couldn't find it in himself to hold the city's business community equally responsible.

If he had, of course, that would have brought his son-in-law Jared Kushner's family into the line of fire. The Kushners own and operate low-income housing developments in the Baltimore area that have been plagued with allegations of legal abuses and have been fined by local authorities for more than 170 building code violations.

Trump's distaste for cities like Baltimore isn't new. But the president has done little for troubled urban areas other than to use them as political punching bags from time to time. So what compelled him to lash out against Cummings and Baltimore this time?

Some of Trump's language and bile was clearly inspired by and directly lifted from a "Fox & Friends" segment that aired Saturday morning about an hour before he first tweeted at Cummings.

The congressman has been an aggressive critic of the humanitarian crisis along the U.S.'s southern border that was sparked by the president's immigration policies, and it was the Fox piece that first tried to argue that conditions on the border were better than in parts of Baltimore.

The House Oversight Committee, which Cummings oversees, also voted recently to subpoena personal email and texts used by top White House aides, including Kushner and his wife, Ivanka Trump — which undoubtedly bothers the president.

Finally, and most troubling of all, the White House has concluded that Trump's racist tweets and attacks on politicians of color may be an asset in the 2020 presidential campaign because it will resonate strongly "among his political base," according to The Washington Post.

Timothy L. O'Brien is the executive editor of Bloomberg Opinion. His books include "TrumpNation: The Art of Being The Donald."