Liberal documentarian Michael Moore trained his fire on Inauguration Day not on Donald Trump but on the party tasked with opposing his presidency.

"The old guard of the Democratic Party has to go," Moore told a group of protesters in Washington on Friday.

He added that "we know now that [Vermont Sen.] Bernie Sanders would have won." Democratic nominee Hillary Clinton defeated Sanders after a testy primary last year, and Sanders remains a key figure in the party even though he is an independent.

He called for the party's establishment to look toward younger people to fill the void and carry the mantle to challenge Trump in four years.

"Donald Trump will not last there four years," Moore said.

Moore is director of films such as "Roger and Me" and "Fahrenheit 9/11." He starred in a one-man show called "Michael Moore in Trumpland" last year that was released right before the election.