The killing of Qassem Soleimani, the commander of Iran’s Islamic Revolutionary Guard Corps, by a U.S. drone strike led left-wing critics of President Donald Trump to take to the streets in more than dozens of American cities to protest what they denounced as a drift toward war.

But while those demonstrators despise Trump, and denounced the killing as an attempted distraction from Democrats’ efforts to impeach him, their opposition to conflict with Iran was also supported by one of the president's loudest and most influential cheerleaders.

While both the Republican Party and conservative media pundits largely united in celebrating Trump for ordering Soleimani’s death, there was one prominent and crucial exception. Fox News host Tucker Carlson delivered a stinging rebuke to the administration over the attack.

Carlson is one of Trump’s most devoted supporters and perhaps the single most articulate advocate for Trump’s "America First" foreign policy philosophy. But Carlson was appalled not just by Trump's decision, but also by what he framed as a victory for "neocons [whose] objective all along" has been regime change in Tehran. He ended his TV attack by declared, "Washington has wanted war with Iran for decades. They have been working toward it. They may have finally gotten it."

Carlson, whose audience exceeds that of his competition on the two rival CNN and MSNBC news networks combined - prides himself on his access to Trump. Only last June, he boasted on air that he'd persuaded the president to reject military retaliation against Iran, after it shot down a U.S. drone.

'War maybe disaster for America, but for Bolton and his fellow neocons, it's always good business.'

At that time, Carlson roasted then National Security Advisor John Bolton as a "bureaucratic tapeworm" and said that had Trump gone ahead and struck Iran, it would have "ended his political career in a minute" and definitively ended his chances of re-election.

Less than three months later, Bolton resigned. Trump’s hostility to Iran and his desire to destroy the nuclear pact concluded with Tehran by his predecessor Barack Obama was undiminished. But so long as Carlson had his ear, it appeared as if he would always pull back from military confrontation with Iran.

Indeed, Tehran seemed to indicate that it believed it had little to lose by continued provocations up to and including last week’s attack that led to the death of a U.S. contractor, and the subsequent orchestrated assault on the U.S. embassy in Baghdad. Trump’s pullout from the nuclear deal and re-imposition of sanctions had crippled their economy and imposed hardships on the IRGC’s ability to fund its terrorist auxiliaries.

But with Trump’s pullout of American troops from northeastern Syria, and Carlson’s ability to talk Trump out of military action against them in mind, they may have not unreasonably concluded that "America First" was as isolationist in nature as its historic namesake that tried to keep the U.S. out of the war with Nazi Germany.

So the strike that killed Soleimani and the head of Iran’s Iraqi terrorist units was not just a body blow to the theocracy’s leadership structure, it also indicated that the neo-isolationist wing of the GOP, for which Carlson is a spokesperson, is losing the struggle for control of Trump’s foreign policy.

This series of events tells us a great deal not just about the future of policy towards Iran, but also the nature of the Trump presidency.

Open gallery view Iranians set a US and an Israeli flag on fire during a mourning procession for military commander Qassem Soleimani and Iraqi paramilitary chief Abu Mahdi al-Muhandis. Tehran, January 6, 2020 Credit: AFP

It turns out that the president’s foreign policy instincts may be in sync with that of Carlson and other isolationists when it comes to Europe or the notion of "nation building." But when it comes to Iran, Trump needs no prodding from the likes of Bolton to act like a neo-conservative. Just as important, the entire notion of anyone - be it Carlson, former White House senior advisor Steve Bannon, or any cabinet official like Secretary of State Mike Pompeo, being able to control Trump is a myth.

Trump’s stands may be inconsistent: his willingness to confront Iran has always been at odds with both his desire for a rapprochement with Vladimir Putin’s Russia, and his belief that the U.S. should avoid foreign entanglements.

But Trump is charting his own course and regardless of its wisdom, he will take the GOP, the conservative movement as well as the minority of American Jews who are more devoted to his re-election than ever, down any path he wants on any issue, including the ongoing struggle with Iran.

While Carlson attempted to make the case that killing Soleimani was a mistake, he did so in a manner that avoided any criticism of the man who made the decision: he still understands who has the affection of his audience. Trump’s name never came up during his monologue that attempted to argue that Iran was no threat to the United States so long as it stayed at home and minded its own business. Instead, Carlson impotently directed his abuse at a Republican critic of Trump like Nebraska Senator Ben Sasse and Bolton, neither of whom have any influence in the White House.

Should this lead to more American casualties, or unknowable complications, public opinion may turn on the president. But what Carlson seems to have misunderstood about the president is that while the president shares his antipathy for Middle East wars, Trump understands that the problem with Obama’s nuclear deal was not just its weak terms, but that it empowered and enriched a regime that is bent on attacking and undermining the United States and its allies.

Part of his hostility to Tehran may lie in Trump’s innate sympathy for Israel and Israeli Prime Minister Benjamin Netanyahu - a sentiment that is as puzzling to figures on the right like Carlson, who have little liking for the Jewish state, as it is to left wing critics of the Likud-led government or to Zionism.

Though his basic knowledge of foreign policy may be limited, Trump’s instinctual distrust of and hostility for the foreign policy establishment has also led him to this conclusion. He seems to understand that breaking the wheel of conventional wisdom about the threat from Iran that had allowed the Islamist regime to bluff the West into concessions as it successfully pursued a quest for regional hegemony was a fundamental error that must be reversed.

While Carlson claimed the death of Soleimani would start a war that "Washington" has wanted "for decades," and that Iran is no more a threat to America than Mexico, it seems Trump has caught on to the fact that it the IRGC that has already been waging a war on the West over that time – and that war wasn’t ended by Obama’s deal.

Moreover, Trump also seems to understand that the false choice put forward by both Obama’s old media "echo chamber" and Carlson alike - that the only choices on Iran are appeasement or all-out war - are wrong.

There is no telling whether Iran’s retaliation will lead to a wider conflict that Americans don’t want to fight. But for now, the neoconservative conviction that a generational war with a rogue regime in Tehran shouldn’t be lost by default seems to have, to the utter frustration of both right-wing isolationists and left-wing opponents of the projection of American power, a convert in Donald Trump.

Jonathan S. Tobin is editor in chief of JNS (the Jewish News Syndicate) and a contributing writer for National Review. Twitter: @jonathans_tobin