With his declaration Friday that the Iran nuclear deal is not in the national interest, President Donald Trump may have put us on the road to war with Iran.

Indeed, it is easier to see the collisions that are coming than to see how we get off this road before the shooting starts.

After “de-certifying” the nuclear agreement, signed by all five permanent members of the Security Council, Trump gave Congress 60 days to reimpose the sanctions that it lifted when Teheran signed.

If Congress does not reimpose those sanctions and kill the deal, Trump threatens to kill it himself.

Why? Did Iran violate the terms of the agreement? Almost no one argues that — not the UN nuclear inspectors, not our NATO allies, not even Trump’s national security team.

Iran shipped all its 20 percent enriched uranium out of the country, shut down most of its centrifuges, and allowed intrusive inspections of all nuclear facilities. Even before the deal, 17 U.S. intelligence agencies said they could find no evidence of an Iranian nuclear bomb program.

Indeed, if Iran wanted a bomb, Iran would have had a bomb.

She remains a non-nuclear-weapons state for a simple reason: Iran’s vital national interests dictate that she remain so.

As the largest Shiite nation with 80 million people, among the most advanced in the Mideast, Iran is predestined to become the pre-eminent power in the Persian Gulf. But on one condition: Avoid the great war with the United States that Saddam Hussein failed to avoid.

Tehran does not want war with us. It is the War Party in Washington and its Middle East allies — Bibi Netanyahu and the Saudi royals — who hunger to have the United States come over and smash Iran.

Yet, even earlier collisions with Iran may be at hand.

In Syria’s east, U.S.-backed and Kurd-led Syrian Democratic Forces are about to take Raqqa. But as we are annihilating ISIS in its capital, the Syrian army is driving to capture Deir Ezzor, capital of the province that sits astride the road from Baghdad to Damascus.

Its capture by Bashar Assad’s army would ensure that the road from Baghdad to Damascus to Hezbollah in Lebanon remains open.

If the U.S. intends to use the SDF to seize the border area, we could find ourselves in a battle with the Syrian army, Shiite militia, the Iranians, and perhaps even the Russians.

The Kurdistan Regional Government voted last month to secede. This raised alarms in Turkey and Iran, as well as Baghdad. An independent Kurdistan could serve as a magnet to Kurds in both those countries.

Baghdad’s army is moving on Kirkuk to prevent its amputation from Iraq in any civil war of secession by the Kurds.

Where does Iran stand in all of this?

In the war against ISIS, they were de facto allies. For ISIS, like al-Qaida, is Sunni and hates Shiites as much as it hates Christians. But if the U.S. intends to use the SDF to capture the Iraqi-Syrian border, Syria, Iran, Hezbollah and Russia could all be aligned against us.

We Americans are coming face to face with some new realities.

The people who are going to decide the future of the Middle East are the people who live there. And among these people, the future will be determined by those most willing to fight, bleed and die for years and in considerable numbers to realize that future.

Our erstwhile allies in the Middle East naturally want us to fight their 21st-century wars, as the Brits got us to help fight their 20th-century wars.

But Donald Trump was not elected to do that. Or so at least some of us thought.