WASHINGTON (AP) — Donald Trump endangered the lives of all members of Congress when he aimed a mob of supporters "like a loaded cannon" at the U.S. Capitol, House Democrats said Tuesday in making their most detailed case yet for why the former president should be convicted and permanently barred from office.

The legal brief forcefully links Trump's baseless efforts to overturn the results of the presidential election to the deadly Jan. 6 riot at the Capitol, saying he bears "unmistakable" blame for actions that directly threatened the underpinnings of American democracy. It argues that he must be found guilty when his impeachment trial opens before the Senate next week on a charge of inciting the siege.

"His conduct endangered the life of every single Member of Congress, jeopardized the peaceful transition of power and line of succession, and compromised our national security," the Democratic managers of the impeachment case wrote. "This is precisely the sort of constitutional offense that warrants disqualification from federal office." 

The legal brief lays out for the first time the arguments House lawmakers expect to present at the impeachment trial. It not only explicitly faults him for his role in the riot but also aims to preemptively rebut defense claims that Trump's words were somehow protected by the First Amendment or that an impeachment trial is unconstitutional, or even unnecessary, now that Trump has left office. It says Trump's behavior was so egregious as to require permanent disqualification from office. 

The Constitution specifies that disqualification from office can be a punishment for an impeachment conviction.

"This is not a case where elections alone are a sufficient safeguard against future abuse; it is the electoral process itself that President Trump attacked and that must be protected from him and anyone else who would seek to mimic his behavior," the legal brief states.

Lawyers for Trump are expected to file their own brief Tuesday. In a Fox News appearance Monday night, one of the attorneys, David Schoen, said he would argue that the trial was unconstitutional, that efforts to bar Trump from office were undemocratic. and that his words were protected by the First Amendment.

Democrats made clear that they disagree with all points.

"The only honorable path at that point was for President Trump to accept the results and concede his electoral defeat. Instead, he summoned a mob to Washington, exhorted them into a frenzy, and aimed them like a loaded cannon down Pennsylvania Avenue," they wrote.