WASHINGTON — Reduced to their weakest state in a generation, Democratic Party leaders will gather in two cities this weekend to plot strategy and select a new national chairman with the daunting task of rebuilding the party’s depleted organization. But senior Democratic officials concede that the blueprint has already been chosen for them — by an incensed army of liberals demanding no less than total war against President Trump.

Immediately after the November election, Democrats were divided over how to handle Mr. Trump, with one camp favoring all-out confrontation and another backing a seemingly less risky approach of coaxing him to the center with offers of compromise.

Now, spurred by explosive protests and a torrent of angry phone calls and emails from constituents — and outraged themselves by Mr. Trump’s swift moves to enact a hard-line agenda — Democrats have all but cast aside any notion of conciliation with the White House. Instead, they are mimicking the Republican approach of the last eight years — the “party of no” — and wagering that brash obstruction will pay similar dividends.

Gov. Jay Inslee of Washington, vice chairman of the Democratic Governors Association, said there had been a “tornado of support” for wall-to-wall resistance to Mr. Trump. Mr. Inslee, who backed a lawsuit against the president’s executive order banning refugee admissions and travel from seven majority-Muslim countries, said Democrats intended to send a stern message to Mr. Trump during a conference of governors in the nation’s capital.