U.S. President Donald Trump, flanked by U.S. Senator Jeff Flake , pauses before speaking to reporters prior to a lunch meeting with Senate Republicans at the White House in Washington, U.S. December 5, 2017.  REUTERS/Jonathan Ernst - RC1118597410

President Trump and Sen. Jeff Flake, R-Ariz., have butted heads over a variety of issues, including the president's rhetoric regarding the media and a special election race.  (Reuters/Jonathan Ernst)

Inside the Trump-Flake feud, from media criticisms to immigration

Arizona Sen. Jeff Flake isn’t running for re-election, but that doesn’t mean he’s taking a step back from battling President Trump.

The fracas between Flake and Trump has grown over disagreements on immigration, the president’s harsh rhetoric regarding the media and an Alabama special Senate election.

Read on for notable fights between the two Republicans.

Trump vs. Stalin

Flake gave a speech on the Senate floor on Jan. 17 in which he blasted Trump’s harsh rhetoric regarding the media.

Flake pointed to times when foreign “dictators and authoritarians” – such as Syrian President Bashar al-Assad, Philippines President Rodrigo Duterte and Venezuelan President Nicolás Maduro – used the term “fake news,” a phrase Trump has often uttered regarding media coverage.

Flake said Trump has “inspired dictators and authoritarians with his own rhetoric.”

Flake also compared Trump’s rhetoric to that of former Soviet dictator Joseph Stalin.

“The ‘enemy of the people’ was how the president of the United States called the free press in 2017. Mr. President, it is a testament to the condition of our democracy that our own president uses words infamously spoken by Joseph Stalin to describe his enemies.”

Flake said, “2018 must be the year that the truth takes a stand against the power that would weaken it.”

‘Jeff Flake(y)’

In criticizing Flake online, Trump gave the senator one of his notorious nicknames: “Jeff Flake(y).”

“Sen. Jeff Flake(y), who is unelectable in the Great State of Arizona (quit race, anemic polls) was caught (purposely) on ‘mike’ saying bad things about your favorite President. He’ll be a NO on tax cuts because his political career anyway is ‘toast.’”

GOP will be ‘toast’

Flake was caught on a hot mic in Nov. 2017 telling a Republican mayor that, “if we become the party of Roy Moore and Donald Trump, we’re toast.”

Flake later admitted to the comment on Twitter, saying “no news here.”

“I’ve been saying this to anyone who will listen,” Flake said.

Flake remained in stalwart opposition to Roy Moore, the beleaguered Republican Alabama Senate candidate in a special election last year. Moore, accused by multiple woman of sexual misconduct when they were in their teens, lost to Democrat Doug Jones.

Flake donated to Jones’ campaign.

Ending Flake’s Senate career

In a scathing speech from the Senate floor, Flake announced on Oct. 24, 2017 that he would not run for re-election. In his announcement, Flake took shots at Trump and the Republican Party, calling the president “reckless, outrageous and undignified.”

White House press secretary Sarah Sanders later said Flake’s decision to leave the Senate “is probably a good move” because of “the lack of support he has in Arizona.”

Flake faced a tough primary, and his favorability ratings in Arizona decreased after he began combating the president.

Trump discussed spending $10 million to defeat Flake if he had decided to run for re-election, Politico reported.

‘Weak’

Trump blasted Flake as “weak” multiple times on social media.

“The Republican Party needs strong and committed leaders, not weak people such as [Flake], if it is going to stop illegal immigration,” he tweeted on Sept. 4, 2016.

“The Great State of Arizona, where I just had a massive rally (amazing people), has a very weak and ineffective Senator, Jeff Flake. Sad!” he said in another tweet.

In Aug. 2017, Trump tweeted, “Phoenix crowd last night was amazing – a packed house. I love the Great State of Arizona. Not a fan of Jeff Flake, weak on crime & border!”

‘Conscience of a Conservative’

Flake went after Trump – as well as his own party – in a book published by Random House called “Conscience of a Conservative.”

In his book, Flake called Trump “a candidate who entertained [voters] and offered oversimplified answers” to complex issues.

Kelli Ward endorsement

Before Flake announced that he would not seek re-election, Trump had already issued his public support for his Republican challenger.

“Great to see that Dr. Kelli Ward is running against Flake Jeff Flake, who is WEAK on borders, crime and a non-factor in Senate,” Trump tweeted on Aug. 17. “He’s toxic!”

Ward, a controversial Republican candidate, previously challenged Sen. John McCain’s Arizona seat and lost.

Election Day

Flake eventually revealed that he did not vote for Trump in the 2016 presidential election.

“I am a Republican. I am a conservative. I would love to have a Republican president but not at any cost,” Flake told NBC.

Flake goes to a mosque

During the presidential election, Flake visited a mosque in Arizona where he told Muslim worshipers that his “hope and prayer today is that the isolated voices calling for division are overwhelmed by the chorus of voices, like those in this room today, calling for acceptance, for tolerance and inclusion,” the Arizona Republic reported.

He blasted Trump’s comments about Muslims during the campaign, calling them “the antithesis of all we stand for here in America.”

Flake’s visit was in December 2015; he said then that he did not think Trump would become the GOP presidential nominee.

Kaitlyn Schallhorn is a Reporter for Fox News. Follow her on Twitter @K_Schallhorn.