A senior Democratic senator warned Friday that the U.S. is failing to defend against continuing cyber attacks by China, Russia and other countries, urging the Trump administration to show resolve to retaliate, including through economic sanctions and military action.

Senator Mark Warner of Virginia, the top Democrat on the Senate Intelligence Committee, complained that U.S. defenses against devastating computer hacks are scattershot and unorganized.

Warner, who was a telecommunications entrepreneur before his political career, urged sweeping changes in the U.S. approach to cybersecurity including shifting defense spending, more visible presidential leadership on cyber and imposing consequences on social media companies if they don’t act to stop the spread of “truly defamatory content.”

Twitter Inc., Facebook Inc. and their peers should have responsibility to take down defamatory misinformation, and if they don’t show they will do so “Congress will have to act on its own,” he said.

“Our personal, corporate, and government data is being bled from every network every day; our faith in institutions and our tolerance for one another is being eroded by misinformation,” he said Friday in a speech at the Center for New American Security. “This is leaving us exposed as individuals and vulnerable as a country. It’s time that we dramatically shift how we view these threats.”