When Joe Biden became president, the Middle East was calm. Now it’s in the midst of a multifront war.

So quiet was the inheritance from the prior Trump administration that nearly three years later, on Sept. 29, 2023 — and just eight days before the Oct. 7 Hamas massacre of Israelis — Biden’s national security adviser, Jack Sullivan, could still brag, “The Middle East region is quieter today than it has been in two decades.”

So, what exactly happened to the inherited calm that led to the current nonstop chaos of the present?

In a word, theocratic Iran — the nexus of almost all current Middle East terrorism and conflict — was unleashed by Team Biden after having been neutered by the Trump administration.

Biden-Harris adopted a five-step revisionist protocol that appeased and encouraged Iran and its terrorist surrogates Hamas, Hezbollah and the Houthis.

The result was a near guarantee that something akin to the Oct. 7 massacres would inevitably follow — along with a subsequent year of violence that has now engulfed the Middle East.

First, on the 2020 campaign trail, Biden damned long-time American ally Saudi Arabia as a “pariah.”

He overturned the policies of both the previous Obama and Trump administrations by siding with the Iranian-supplied terrorist Houthis in their war on Saudi Arabia.

Biden accused the kingdom of war crimes, warning it would “be held accountable” for its actions in Yemen. Biden-Harris took the murderous Houthis off the US terrorist list.

Almost immediately followed continuous Houthi attacks on international shipping, Israel and US warships — rendering the Red Sea, the entryway to the Suez Canal, de facto closed to international maritime transit.

Worse still, by the time of the 2022 midterms, when spiraling gas prices threatened Democratic congressional majorities, Biden opportunistically flipped and implored Saudi Arabia to pump more oil to lower world prices before the November election.

Appearing obnoxious and then obsequious to an old Middle East ally is a prescription for regional chaos.

Second, Biden-Harris nihilistically abandoned the Trump administration’s “Abraham Accords” initiative.

That diplomatic breakthrough had proven a successful blueprint for moderate Arab nations to seek détente with Israel, ending decades of hostilities to unite against the common Middle East threat of Iran.

Third, Biden begged Iran to reenter the appeasing, so-called Iran Deal that virtually ensured Iran would eventually get the bomb.

Worse yet, it dropped oil sanctions against the theocracy, allowing a near-destitute Iran to recoup $100 billion in profits.

And it greenlighted $6 billion in hostage ransoms to Tehran.

An enriched Tehran immediately sent billions in support and weapons to the anti-Western terrorists of Hamas, Hezbollah and the Houthis to attack Israel, Americans, and international shipping.

Iran soon began partnering with China and Russia to form a new anti-American axis.

Biden-Harris also fled abruptly from Afghanistan, abandoning billions in weapons and American contractors. The humiliation thus virtually destroyed American deterrence in the Middle East, inciting enemies and endangering friends.

Fourth, Biden-Harris restored hundreds of millions of dollars in aid to the West Bank and Gaza, but without any guarantees that the Palestinian Authority and Hamas would desist from their past serial terrorist acts.

In the case of Hamas, US and Western “humanitarian aid” simply freed up more fungible dollars in Gaza to arm Hamas and to expand its subterranean tunnel complex essential to its Oct. 7 massacres and hostage-taking.

Fifth, from the outset of the ensuing increased tensions, Biden-Harris began pressuring the Israelis to act “proportionally” in responding to the massacre of some 1,200 Israelis and nearly 20,000 missiles, rockets and drones launched at their homeland from Iran, the Houthis, Hamas and Hezbollah.

Such straitjacketing of our closest Middle East friend further signaled to the Iranian-backed terrorists that there was now “daylight” between the United States and its closest regional ally. That opportunity provided still further incentives for Iran to test just how far it could safely go in attacking Israel.

But why did Biden-Harris so foolishly ignite the Middle East?

In part, the administration naively tried to resurrect the old, discredited Obama administration notion of “creative tension” — empowering a rogue Iran and its terrorists to play off Israel and the moderate Arab regimes, as a new sort of balance of power in the region.

In part, Biden-Harris was caving to increased antisemitism at home and the rise of powerful, pro-Palestinian groups on US campuses and in critical swing Electoral College states.

In part, Biden-Harris was naive and gullible. The two bought into the anti-Americanism and anti-Israel boilerplate of our enemies.

So, they thought to make amends by seeing Iran and its terrorists as the moral equivalent of democratic, pro-American Israel.

Their malignant legacy is the current Middle East disaster.