Tuesday Briefing

J.D. Vance, once a critic of Donald Trump, is now his running mate.Credit…Haiyun Jiang for The New York Times

J.D. Vance is Trump’s pick for vice president

On the first day of the Republican National Convention, Donald Trump announced his running mate: J.D. Vance, a 39-year-old senator and ex-Marine who, over the last few years, has transformed from a sharp critic of the former president into one of his most loyal allies.

Vance is an ambitious ideologue who relishes the spotlight and has shown he can energize donors. He has been a vocal opponent of U.S. aid for Ukraine, leading an unsuccessful campaign in the Senate to block a $60 billion package. If Trump wins a second term, Vance’s selection will position him as a potential successor. Here’s what to know about him.

Trump: The former president, his right ear bandaged, made his first public appearance since a gunman tried to kill him on Saturday night. People at the convention pumped their fists and shouted “fight,” echoing the gesture Trump made as the Secret Service rushed him to safety. That moment has become a rallying point for his supporters.

Assassination attempt: Former high schoolclassmates described the gunman, Thomas Crooks, as intelligent but solitary, someone who tried to avoid being teased. The F.B.I. said it had gained access to his phone, but it was not immediately clear whether it had yielded clues.

Classified documents case: In a bombshell decision, a federal judge, Aileen Cannon, threw out all the charges against Trump involving his handling of classified documents, ruling that the special counsel who filed the indictment had been unconstitutionally appointed to his job. The ruling upended 25 years of Justice Department procedure.