"We have to have our own vision for the future, but everybody knows that we must be unified in making sure that he doesn't have a second term," she said.
She argued that any of the Democratic candidates "would be a better president than the current occupant of the White House, but we want to be very positive about how we go forth."
Pelosi also defended her decision to rip up Trump's State of the Union address earlier this month.
Pelosi reiterated that she had no intention of tearing up her copy of Trump's annual address to Congress, but that as she read along, "realized that almost every page had something in it that was objectionable."
The tension on display at this year's State of the Union came a day before the GOP-led Senate was expected to and eventually voted to acquit Trump of two articles of impeachment.
"You can't have an acquittal unless you have a trial and you can't have a trial without witnesses and documents. So he can say he was acquitted, and the headlines can say acquitted but he's impeached forever," Pelosi told Christiane Amanpour on the sidelines of the Munich Security Conference.
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