Richard Painter, the former chief White House ethics lawyer in the George W. Bush administration, blasted the prospect of former US Ambassador to the UN John Bolton replacing General H. R. McMaster as President Donald Trump’s national security adviser — a prospect that came to fruition Thursday.

“John Bolton was by far the most dangerous man we had in the entire eight years of the Bush Administration,” Painter tweeted last Friday. “Hiring him as the president’s top national security advisor is an invitation to war, perhaps nuclear war.”

Painter ended his post with a blunt and stark sentence: “this must be stopped at all costs.” He also linked to an article in the Atlantic titled “Hiring John Bolton Would Be a Betrayal of Donald Trump’s Base.”