Lead House impeachment manager Adam Schiff (D-Calif.) claimed in his closing arguments during the Senate trial Monday that President Trump cannot be trusted to shun further foreign interference in the election and that voting to remove him from office is the only solution.

Why it matters: Sen. Lamar Alexander (R-Tenn.), who has said that Trump's campaign to pressure Ukraine to investigate the Bidens was "inappropriate" but not impeachable, suggested on Sunday that the impeachment process will make the president "think twice" about soliciting foreign interference in the future.

Sen. Joni Ernst (R-Iowa) also suggested on CNN Sunday that Trump has learned his lesson and that he knows he should go through "proper channels" when trying to "ferret out corruption" in other countries.

What he's saying:

"We must look at the history of this presidency and to the character of this president, or lack of character, and ask: Can we be confident that he will not continue to try to cheat in that very election? Can we be confident that Americans, and not foreign powers, will get to decide, and that the president will shun any further foreign interference in our democratic affairs? And the short, plain, sad, incontestable answer is no, you can't. ... He will not change, and you know it."

— Adam Schiff

Go deeper ... Live updates: Closing arguments begin in impeachment trial