Contrary to common belief, the first major politician on the New Jersey scene to back Donald Trump was not Chris Christie.

It was Mike Doherty. The Republican state senator from Warren County is a West Point grad who served in an artillery battery in Germany during the Cold War. That gave him time to think of what would happen if those tactical nukes were fired in anger.

And that in turn made him side with candidate Trump when he Tweeted things like “Saudi Arabia should fight their own wars, which they won’t, or pay us an absolute fortune to protect them and their great wealth - $ trillion.”

Doherty texted that to me the other day, followed by a recent Trump quote:

“Saudi Arabia oil supply was attacked. There is reason to believe we know the target and are locked and loaded depending on verification, but are waiting to hear from the Kingdom as to who they believe was the cause of the attack and under what terms we would proceed.”

When I gave him a call, Doherty said that tweet represents the opposite of everything Trump promised during the campaign.

“We’re going to let Saudi Arabia dictate when we go to war?” he asked. “That’s contrary to everything in ‘America first.’ What happened to Trump?”

What happened was that he got kidnapped by the same inside-the-Beltway foreign policy establishment that he ran against in 2016. That crowd somehow managed to convince him that it is the proper role of the U.S. military to protect against the threat posed by Yemen.

One problem: There is no threat from Yemen, at least to the U.S. It’s a poor, crowded country on Saudi Arabia’s southern border where a bunch of mountain people called the Houthis are engaged in a civil war against the Saudi-backed government, which of course is corrupt and inefficient.

The Saudis have been bombing the hell out of the Houthis - with American logistical help - since way back in the Obama administration. So it is hardly surprising that the Yemenis would strike back at Saudi Arabia’s weakest point.

It’s certainly not surprising to Bob Baer, the former CIA agent who spent most of his career in the Mideast. In 2003, he authored a book titled, “Sleeping with the Devil: How Washington Sold Our Soul for Saudi Crude.”

When I gave Baer a call, the first thing he said was “Read the first chapter of my book.”

I dug out my dog-eared copy. Sure enough, the book began with a scenario envisioning in great detail an attack on Abqaig, the Saudi oil-processing facility blown up the other day in that aerial attack for which the Yemenis claimed credit.

“Taking down Saudi Arabia’s oil infrastructure is like spearing fish in a barrel,” Baer wrote back then. “It’s not a question of opportunity; it’s a question of how good your bang men are and what you give them to work with.”

After the book came out, the Saudi government reached out to Baer to say he was wrong about the vulnerability of Abqaig. He found their arguments unpersuasive.

“I knew this was going to happen,” he said. “They’re just killing Yemenis right and left. We’re always surprised when these Third World countries snap back at us.”

Now that Yemen has snapped back at the Saudis, Baer said, the sheiks have to be worried about the many other weak points in their oil infrastructure.

“If they couldn’t catch these 10 drones coming in, what makes you think they’ll catch 10 more?” he asked.

Baer says the simple solution is “Just stay out of the Mideast. It’s like sticking your (slang term for a male organ) into a wasp’s nest.”

That’s the sort of thing Trump might have said back when he was campaigning. Doherty said the president needs to keep those promises.

“He’s gonna lose a lot of support if he gets us into a war,” said Doherty.”If he thinks this is gonna get him re-elected, he’s mistaken.”

He is indeed. The same liberal internationalist/neoconservatives who called him an isolationist for wanting to stay out of war will call him a hawk for wanting to get into a war.

President Trump needs to go back and read candidate Trump’s foreign policy statements.

That guy was onto something.