President Donald Trump ridiculed Sen. Mitt Romney as an “ass” on Saturday after the failed Republican presidential candidate criticized him.

“Mitt Romney never knew how to win. He is a pompous ‘ass’ who has been fighting me from the beginning,” Trump wrote on Twitter.

Mitt Romney never knew how to win. He is a pompous “ass” who has been fighting me from the beginning, except when he begged me for my endorsement for his Senate run (I gave it to him), and when he begged me to be Secretary of State (I didn’t give it to him). He is so bad for R’s! — Donald J. Trump (@realDonaldTrump) October 5, 2019

Trump recalled that Romney begged him to appoint him as Secretary of State and later begged him for a campaign endorsement when he was running for Senate.

In recent weeks, Romney has vocally expressed his concern about Trump’s public call for China and Ukraine to investigate former Vice President Joe Biden and his son Hunter Biden for corruption.

“Somebody please wake up Mitt Romney and tell him that my conversation with the Ukrainian President was a congenial and very appropriate one, and my statement on China pertained to corruption, not politics,” Trump wrote.

On Friday, Romney called Trump’s request to foreign countries to investigate the Bidens’ corruption “wrong and appalling.”

Trump reminded his followers that Romney “choked” when he challenged President Barack Obama in the 2008 election.

“If Mitt worked this hard on Obama, he could have won,” Trump wrote. “Sadly, he choked!”

Later in the day, Trump said Romney was worse than former Sen. Jeff Flake of Arizona, who frequently criticized the president before deciding not to run for election.

“Jeff Flake is better!” he wrote to Fox News correspondent Kevin Corke.

Trump also questioned whether Romney still had support from Republicans in Utah.

“I’m hearing that the Great People of Utah are considering their vote for their Pompous Senator, Mitt Romney, to be a big mistake,” Trump wrote. “I agree! He is a fool who is playing right into the hands of the Do Nothing Democrats!”

He then shared the hashtag #IMPEACHMITTROMNEY

Somebody please wake up Mitt Romney and tell him that my conversation with the Ukrainian President was a congenial and very appropriate one, and my statement on China pertained to corruption, not politics. If Mitt worked this hard on Obama, he could have won. Sadly, he choked! — Donald J. Trump (@realDonaldTrump) October 5, 2019

I’m hearing that the Great People of Utah are considering their vote for their Pompous Senator, Mitt Romney, to be a big mistake. I agree! He is a fool who is playing right into the hands of the Do Nothing Democrats! #IMPEACHMITTROMNEY — Donald J. Trump (@realDonaldTrump) October 5, 2019

No Kevin, Jeff Flake is better! https://t.co/IyENBffEjp — Donald J. Trump (@realDonaldTrump) October 5, 2019

Trump and Romney have a contentious political relationship that started when Romney asked the famous billionaire to endorse him for president in the 2008 campaign. Despite Trump’s effusive praise for Romney in his failed run for president, Romney did not return the favor in 2016.

During the 2016 Republican primary, Romney famously attempted to stop Trump with a lengthy “never Trump” speech, deriding Trump as a “con-man.” In response, Trump derided Romney as a “choker” and mocked him for walking like a penguin.

When Trump won the 2016 election, Romney met with Trump at his club in New Jersey to discuss a possible job as Secretary of State, but Trump turned him down.

Romney ran for Senator of Utah instead and asked Trump for his endorsement, which the president gave.