President Trump with House Speaker Paul D. Ryan (R-Wis.) after the passage of the tax bill on the South Lawn at the White House on Dec. 20, 2017. (Jabin Botsford/The Washington Post)

When House Speaker Paul D. Ryan (R-Wis.) announced that he wouldn’t seek reelection in April 2018, President Trump was effusive, calling him a “truly good man” with a “legacy of achievement that nobody can question.”

But that was before Ryan blasted Trump in the upcoming book “American Carnage,” telling author Tim Alberta that the president “didn’t know anything about government” and operates on ill-informed “knee-jerk reactions.”

Late on Thursday, Trump swung back at the former speaker. In a three-tweet barrage, Trump called Ryan’s leadership “atrocious,” labeled him a “lame duck failure” and suggested he was thrilled when Ryan left Capitol Hill.

“He had the Majority & blew it away with his poor leadership and bad timing. Never knew how to go after the Dems like they go after us. Couldn’t get him out of Congress fast enough!” Trump tweeted.

The volley of insults marks the nadir of a volatile relationship between Trump and the former top-ranking House Republican, who pushed the party to dump the real estate mogul after the “Access Hollywood” tape and refused to campaign with the presidential nominee, but then later battled to push Trump’s agenda through Congress.

As The Washington Post’s Josh Dawsey reported on Thursday, Ryan immolated whatever bridges the two GOP leaders had built after Trump’s election with his incendiary comments to Alberta. Ryan told the Politico Magazine writer that he viewed his congressional exit as an “escape hatch” from a president whose leadership he deplored.

“We’ve gotten so numbed by it all,” Ryan said. “Not in government, but where we live our lives, we have a responsibility to try and rebuild. Don’t call a woman a ‘horse face.’ Don’t cheat on your wife. Don’t cheat on anything. Be a good person. Set a good example.”

Ryan described Trump as painfully ignorant and painted a GOP leadership group toiling behind the scenes to “stop him from making bad decisions. All the time.”

Trump, in his typically visceral counterattack, hit back at Ryan as an unsuccessful national candidate who let down Republicans and then abandoned the party.

“Paul Ryan, the failed V.P. candidate & former Speaker of the House, whose record of achievement was atrocious (except during my first two years as President), ultimately became a long running lame duck failure, leaving his Party in the lurch both as a fundraiser & leader,” he tweeted on Thursday.

Trump also claimed that he warned Sen. Mitt Romney (R-Utah) that he would lose to President Barack Obama in 2012 if he picked Ryan as a running mate.

“When Mitt chose Paul I told people that’s the end of that Presidential run,” Trump tweeted.

On Friday, Romney came to Ryan’s defense.

“The fault for our 2012 loss is mine alone; @SpeakerRyan was a tireless campaigner, fundraiser, and conservative champion. As the sole person who could unite the House, he acquiesced to be Speaker as a service to the country,” Romney tweeted.

When Ryan chose to leave Congress last year — an unusual move for a House speaker heading into a hotly contested midterm — he cited a desire to spend more time with his family, though many pointed to his rocky relationship with Trump and differing policy goals.

Trump, though, suggested a different motivation: That Ryan knew he’d lost the support of his home state, where Trump beat Hillary Clinton by less than a percentage point.

“He quit Congress because he didn’t know how to Win,” Trump tweeted. “They gave me standing O’s in the Great State of Wisconsin, & booed him off the stage. He promised me the Wall, & failed (happening anyway!)”

More from Morning Mix:

A German-Iranian father says he was barred from entering the U.S. to bury his son

A white store owner’s call led to a black street musician’s ‘outrageous’ arrest, roiling New Orleans

A gay Catholic schoolteacher was fired for his same-sex marriage. Now, he’s suing the archdiocese.