WASHINGTON — Donald Trump Jr. got straight to the point during the now-famous Trump Tower meeting in June 2016.

“So I believe you have some information for us,” he said, directing his attention across a large conference table to the Russian lawyer who was there, he thought, to deliver incriminating information on Hillary Clinton.

But if Mr. Trump expected a campaign-changing bombshell, he was quickly disappointed. The disparaging information about Mrs. Clinton amounted to no more than allegations of fraud in Russia by several obscure Democratic donors. The Trump campaign officials reacted with dissatisfaction, not eagerness. Both sides left disappointed.

The chasm between expectation and reality surrounding the meeting was one of the dominant themes running through more than 2,500 pages of testimony and documents released by the Senate Judiciary Committee on Wednesday. The committee has been conducting one of the investigations into the Trump campaign’s contacts with Russians, and the documents revealed new details about the run-up and the aftermath of what is thought to be one of the key episodes of the campaign’s interactions with Russia.