Mr. Trump has been the meteorologist in chief, adding constant weather updates to a usual weekend of tweets attacking his enemies and retweeting bits of praise.
If the president did not originally inspire the gunman, he has brought into the mainstream polarizing ideas and people once consigned to the fringes of American society.
Democratic leaders say African-Americans are deeply engaged in this election, but President Trump is also targeting them with Facebook ads. How they react may well determine his future.
Mr. Biden, the front-runner, was confronted over his record on health care and criminal justice, and this time not just from Kamala Harris.
Tonight’s lineup featured 10 candidates including the former Vice President Joe Biden, Senator Kamala Harris of California and Senator Cory Booker of New Jersey.
Moderate underdogs kicked off the Detroit debates by targeting the top candidates with charges of “wish-list economics” and “impossible promises” on health care.
The CNN debate was a clash over health care with moderates along the edge throwing firebombs on the electability of progressives with the boldest policy plans.
House Democrats are moving aggressively to defend their majority, and rushing to protect the seats they hold in districts that supported the president in 2016.
The escalation rattled markets and thrust the world’s two largest economies, which had seemed on the brink of resolving their differences, back into confrontation.
The United States and China escalated their trade dispute on Monday as Beijing announced higher tariffs and the Trump administration prepared to tax all Chinese imports.