Story highlights Massachusetts Sen. Elizabeth Warren said it's time to stop the GOP front-runner Donald Trump

"Donald Trump is a bigger, uglier threat every day that goes by," she wrote in a Monday Facebook post

(CNN) Massachusetts Sen. Elizabeth Warren said it was time for voters of all stripes to unite together against GOP front-runner Donald Trump.

"Donald Trump is a bigger, uglier threat every day that goes by -- and it's time for decent people everywhere -- Republican, Democrat, Independent -- to say, 'No More Donald,'" Warren wrote Monday in a Facebook post

Warren, who's not endorsed a Democratic candidate, is an outspoken liberal voice in Congress.

"There's a history of demagogues calling those they disagree with 'terrorists' and using that as justification for intimidation and violence -- and that history is ugly and dangerous. There's also a history of people staying quiet for too long, hoping for the best but watching silently as the threat metastasizes," Warren wrote.