Former House Speaker Newt Gingrich is warning that Democrats’ “very dangerous” rhetoric and behavior could lead to something “serious” against President Donald Trump.

During an interview on Fox News, Gingrich dismissed a claim by House Minority Leader Hakeem Jeffries, D-N.Y., that Republicans are “on the run,” warning that Democrats are in a rage and offering “no solutions.”

Gingrich said the left is resorting to extreme tactics to resist Trump and oppose Elon Musk’s efforts to cut government spending.

“Well, I think that everything you showed earlier reflects what Lincoln said at Gettysburg when he said, this is a test of whether this system or any system so conceived in liberty can survive. You have a hard-line group who believe that they have the right to be violent, that they have the right to deny the American people the choice of their leadership, that they have the right to break the law. The answer to all of that is, frankly, you have to lock them up. You have to enforce the law,” Gingrich began.

“Period. And at some point, people begin to realize that you can’t wage war against the entire American people. And in that sense, I would argue that Elon Musk is simply one of the people serving the American people. He’s a senior advisor to the president of the United States. And I think that, in that sense, all of this is totally unacceptable, as is harassing a Supreme Court justice or harassing the vice president and his three-year-old,” Gingrich added.