Donald Trump’s dramatic ditching of National Security Adviser John Bolton Tuesday rocked American politics, raised new questions about the president’s foreign policy and received instant praise on Fox News – where Bolton spent 10 years as a contributor.

The events surrounding Bolton’s departure – whether or not he offered to resign as he claims, or whether Trump “informed John Bolton last night that his services are no longer needed” – further highlight the strained relationship between the two.

Bolton, the 51st major departure from the Trump administration, had vehemently opposed Trump’s willingness to sit down and talk with both Iranian President Hassan Rohani and the Taliban – so much so that Trump reportedly told several advisers to “keep an eye on Bolton for press leaks and backstabbing.”

Bolton was ceremoniously lambasted by Tucker Carlson hours after Trump tweeted about the national security adviser's dismissal; the Fox News star called Bolton a “man of the left” and his departure “a great day for America.”

In June, Carlson was reportedly central figure in Trump’s last-minute decision to ignore Bolton’s protestations and not bomb in retaliation for Iran’s downing of a U.S. drone in the Persian Gulf.

Carlson, who advised Trump in private, then slammed Bolton. “According to John Bolton, [Iraq is] a raging success,” Carlson said. “We killed hundreds of thousands of people, lost thousands of our own troops, spent more than $1 trillion – all to eliminate a WMD threat that, despite John Bolton’s assurances, never existed in the first place.”

Carlson has long echoed the “America First” foreign policy that Trump unveiled during the 2016 Republican primaries, slaughtering sacred cows in the party. This included attacks on former President George W. Bush over the Iraq War, which Trump said destabilized the Middle East and was based on “lies” about weapons of mass destruction.

Carlson argued that a war with Iran would cost Trump reelection; this helps explain Trump’s seat-of-the-pants strategy to make peace with the Taliban and end the war in Afghanistan before the 2020 election.

Carlson and Bolton also pushed Trump in different directions on North Korea and Syria. Carlson, who accompanied Trump to the Korean Demilitarized Zone in June, has long supported Trump’s rapprochement with Kim Jong Un, while Bolton blocked Trump early this year from trading U.S. economic concessions for dubious promises on North Korean nuclear disarmament.

Bolton was credited with keeping U.S. troops in Syria despite Trump’s America First inclinations. And as Bret Stephens writes in The New York Times, Bolton stopped Trump from “a cynical betrayal of the Kurdish fighters without whom we could not have decimated ISIS” and more importantly stopped Trump from creating a vacuum for “Iran and its proxies, the Bashar al-Assad regime, the Erdogan regime, ISIS remnants” to fill. On his show, Carlson has been pushing hard against any further intervention in Syria.

And as he argued in June about Trump: “Bombing Iran would have ended his political career in a minute. There would be no chance of reelection after that. Ill-advised wars are like doing cocaine: The initial rush rises your poll numbers, but the crash is inevitable.”

Regarding Bolton, Tucker praised Trump’s “especially great” decision “for the large number of young people who would have been killed in pointless wars if Bolton had stayed on the job.”

Bolton, who served as Bush’s UN ambassador and was an architect of the Iraq War, was defended online by MSNBC host and former Republican congressman Joe Scarborough.

Scarborough tweeted, “POTUS considered Bolton

*Insufficiently pro-Taliban

*Insufficiently pro-North Korea

*Insufficiently pro-Russia

*Insufficiently pro-Iranian

Trump wanted to play ‘Let’s Make A Deal’ with those who hate America the most.”

Scarborough’s criticism echoes the sentiments of Republican leaders in Congress like Rep. Liz Cheney of Wyoming. The daughter of former vice president and Bolton colleague Dick Cheney wrote that “Camp David is where America’s leaders met to plan our response after al Qaeda, supported by the Taliban, killed 3000 Americans on 9/11.

“No member of the Taliban should set foot there. Ever.”

Carlson tried to explain why Bolton’s firing might ruffle some feathers. “If you are wondering why so many progressives are mourning Bolton’s firing tonight, Bolton himself fundamentally was a man of the left,” he said.

Mitt Romney, now a Utah senator, and Samantha Power, a UN ambassador under Barack Obama, lamented the ouster of Bolton; Carlson called this evidence that Bolton is squarely on the left.

“There was not a human problem John Bolton wasn’t totally convinced could be solved with the elite force of government,” Carlson said. “That’s an assumption of the left. Not the right. Don’t let the mustache fool you. John Bolton was one of the most progressive people in the Trump administration.”

The battle between Bolton and Carlson parallels a fight in the Republican Party between its traditional, establishment foreign policy centered around a strong global military presence and an ascendant isolationist, nationalist foreign policy championed by the likes of Carlson and Sen. Rand Paul of Kentucky.

Tucker: John Bolton refuses to acknowledge his mistakes

Carlson concluded by warning about the many other Boltons in the federal bureaucracy, saying that “war may be a disaster for America, but for John Bolton and his fellow neocons, it’s always good business.”

He went on to slam Trump’s special representative for Iran and contender to replace Bolton, Brian Hook, as an “unapologetic neocon” who “has undisguised contempt for President Trump, and he particularly dislikes the president’s nationalist foreign policy.” Iranian Foreign Minister Mohammad Javad Zarif echoed Carlson hours later in a tweet, arguing that "Thirst for war – maximum pressure – should go with the warmonger-in-chief."