Tucker Carlson has impeccable conservative credentials.

He started out as a low-level staffer at the Heritage Foundation and now he hosts a popular show on Fox News. In between were stints at The Weekly Standard and the on-line publication he co-founded, The Daily Caller. His often contentious prime-time show, Tucker Carlson Tonight, which now occupies Bill O’Reilly’s former slot at Fox, is third in the cable news ratings war behind Sean Hannity and Rachel Maddow.

When Tucker talks, the president listens.

Carlson believes that Donald Trump has been, on balance, a long overdue wake-up call for the Republican Party and an assault weapon that can be used against America’s misguided ruling elite. “Shocking, vulgar, and right,” is how he described Trump in a Politico article back in January 2016.

Since Trump entered the White House, Carlson has occasionally disagreed with the president, but usually for not being sufficiently tough and reactionary, for instance on immigration.

“I think President Trump is interesting, and I agree broadly with his agenda,” he recently told the Heritage publication The Daily Signal.

That’s why his commentary last week on Iran is so important.

Carlson initially supported the Iraq War but then became disenchanted about a year later, along with many others who’d ordered a cakewalk and received a quagmire instead. Now Carlson is warning Trump not to go down the same road as George W. Bush.

If there’s one thing that Washington loves more than open borders and fat lobbying contracts, it’s pointless wars half a world away. Contractors get rich. Neocon intellectuals feel powerful. Bill Kristol, Max Boot, and Nancy Pelosi agree on one thing: War is good as long as the war does not help the United States. …

We are moving toward, however slowly, some kind of confrontation with Iran. And that should worry everybody, but it should especially be of concern to anyone who supported the president.

If President Trump decides to go to war with Iran, it will destroy his presidency just as the Iraq War destroyed the presidency of his Republican predecessor George W. Bush.

Things must be getting pretty hairy if a top Fox News pundit feels that he has to talk the president down from the ledge.

Perhaps Carlson has good reason to be freaked out. In the last 10 days, Secretary of State Mike Pompeo gave a rah-rah rant in favor of regime change in Iran. The president issued an all-caps tweet threatening Tehran with “consequences the likes of which few throughout history have ever suffered before.” And Australian government officials told the press that the Trump administration is prepared to start bombing Iranian nuclear facilities as early as this month.

But, as always, the Trump administration has been aflutter with mixed messages. Pentagon chief James Mattis, for instance, categorically denied the Australian reports. Then, on Monday, the president himself announced that he was willing to meet with Iranian President Hassan Rouhani with “no preconditions… anytime they want.”

As if this weren’t inconsistent enough, even as Trump was talking about a meeting without preconditions, Pompeo was directly contradicting his boss:

If the Iranians demonstrate a commitment to make fundamental changes in how they treat their own people, reduce their malign behavior, can agree that it’s worthwhile to enter into a nuclear agreement that actually prevents proliferation, then the president said he’s prepared to sit down and have the conversation with them.

Since Iran already entered into a nuclear agreement that actually prevents proliferation and since the government (like all governments) thinks it treats its people fine and dandy and behaves properly toward all other countries, Pompeo’s very obvious preconditions are not likely to go down well in Tehran.

The question remains: How likely is a war between the United States and Iran?