After Biden Drops Out, Trump Says He Was ‘Never’ Fit to Be President

Former President Donald J. Trump seized on President Biden’s decision to end his bid for re-election, saying he had never been fit to serve — an attack on his former rival that was immediately followed by other Republicans calling on the president to step down from office as well.

“Crooked Joe Biden was not fit to run for President, and is certainly not fit to serve — And never was!” Mr. Trump wrote on social media shortly after Mr. Biden announced that he was ending his campaign.

The former president’s post did not mention Vice President Kamala Harris, whom Mr. Biden swiftly endorsed to take his place in the race. But Mr. Trump and his allies frequently criticized her during the Republican convention last week.

The former president, who formally accepted his party’s nomination on Thursday night in Milwaukee, also sought to raise money off Mr. Biden’s departure, sending a message to would-be small-dollar donors saying that Mr. Biden had “quit the race in COMPLETE DISGRACE!”

Mr. Trump accused Mr. Biden’s allies of having known for months that the president was unfit to serve in his role because of age and health concerns. Other Republicans quickly followed Mr. Trump’s lead in calling for Mr. Biden to step down.

“If Joe Biden is not fit to run for President, he is not fit to serve as President,” The speaker of the House, Mike Johnson, wrote on X.

Republicans have been planning a strategy aimed at Ms. Harris, presuming that she would be the most likely replacement for Mr. Biden. Mr. Trump himself did not immediately mention her after Mr. Biden’s announcement, but the party’s messaging machinery did.

@RNCResearch, a social media account managed by the G.O.P. and the Trump campaign, was critical of Ms. Harris, accusing her of