MINNEAPOLIS — The House vote to impeach President Donald Trump shifts the action to the Senate, where Minnesota Democrats Amy Klobuchar and Tina Smith have pledged to sit in judgment impartially despite their strong support of the House impeachment inquiry.

Both senators are under pressure to follow the party line, but neither has committed herself to voting to remove the president from office. The issue is likely to be dominant in Smith’s expected tough re-election fight in 2020. And the time demands of the Senate trial could keep Klobuchar off the presidential campaign trail at a critical time.

Under the Constitution and Senate rules, all members must take an oath affirming that they will “do impartial justice according to the Constitution and laws” during the impeachment trial.

“I will go onto the Senate floor and hold up my right hand and swear to deliver impartial judgment,” Smith said in an interview Thursday with The Associated Press, adding she “will not prejudge” without hearing all the evidence.