After months of attacks by Mr. Trump and his allies on the investigation he leads, Mr. Rosenstein described a Russian influence operation that had to be blessed by the Kremlin, and named the perpetrators who carried it out. He did it just three days before Mr. Trump is due to meet in Helsinki, Finland, with the Russian president, Vladimir V. Putin. And he added what some saw as pointed messages to Mr. Trump, who he said has “got to make some very important decisions for our country.”…

Matthew Miller, a spokesman for Eric H. Holder Jr. when he was President Barack Obama’s attorney general, said prosecutors could have waited to seek the indictment until after Mr. Trump came home, and that the decision to move for charges just before the meeting with Mr. Putin might not be purely coincidental.

“None of the people in the indictment are a flight risk,” he said. “It sent a strong signal to the White House that they hold some cards, but the Justice Department has some, too.”