Republicans are lining up to oppose Trump. Will it make a difference?

Donald Trump has a knack for rallying a remarkable range of political opinion around a common goal: preventing his return to the White House.

That now includes prominent names from his own Republican party and top aides who worked under him as president. From former White House officials and national security staff to a once-worshipful press secretary, a host of one-time Trump fans are now lining up to join Democrats in declaring him unfit for another term in office.

White House lawyers who served Republican presidents going back to Ronald Reagan and retired senior military officers have also denounced Trump as a danger to democracy.

The anti-Trump messages are principally aimed at persuading Republicans who may formerly have voted for him that they should put country before party to keep a dangerous populist from a second term in the White House. Opinion polls say that 9% of likely voters who support Trump are prepared to at least consider switching to the Democratic candidate, Kamala Harris.

On Monday, 200 Republicans who worked for President George W Bush and the former presidential candidates Senators Mitt Romney and John McCain, released an open letter in support of Harris and her running mate, the Minnesota governor, Tim Walz.

The letter warned that there was more to fear from Trump than a repeat of his first term because he is now bound up with the authoritarian plan to impose rightwing control across the entire US government, including non-partisan federal agencies, known as Project 2025.

The Trump campaign communications director, Steven Cheung, scorned the letter as written by nonentities.