"Three times a week the Senate Republicans meet for lunch. ... And occasionally they walk into that chamber and take a vote or two or three on judges. That is the sum total of the Senate's work today. Mitch McConnell has effectively turned the United States Senate into a very expensive lunch club," Murphy told reporters.

Votes on legislation have slowed to a crawl, after a bipartisan disaster aid bill stalled amid fighting over Puerto Rico. Republicans have acknowledged that nominations are their priority for the foreseeable future, after accusing Democrats of slow-walking them during Trump's first two years.

For his part, Murphy pushed Tuesday for the Senate to take up background check legislation, after the House passed bill earlier this year.

"It's time for the Senate to stop being a legislative graveyard and start doing the work of the American people, and the background checks bill would be a good place to start," he said.