America’s allies are lining up to mediate between Washington and the Tehran regime. But they’re jumping the gun.

Witness Japan’s President Shinzo Abe, who arrives in Tehran Wednesday for a two-day visit, marking the 90th anniversary of diplomatic relations between his country and Iran. Tokyo officials defend their soft-on-Tehran approach as a “balanced” way to deal with the Mideast. Whatever the merits of that claim, the Abe visit is mostly about oil.

The trip comes shortly after the Japanese leader hosted his golfing buddy President Trump in Tokyo. The symbolism is deliberate: Abe seeks to revive a US-Iranian channel of communication, per Japanese media. And he isn’t alone in his efforts. Germany’s foreign minister, Heiko Maas, was in Tehran this week, trying to buck up confidence in the nuclear deal that Trump ditched.

There is a reason America’s European and Asian allies are determined to end the US quarantine of Iranian businesses. Trump’s increasingly tough sanctions give countries and corporations an uncomfortable pair of options: Buy Iranian oil and invest there, or do business with the US — but you can’t do both.

The latest punishment came last Friday, when the administration vowed to sanction anyone doing business with Iran’s petrochemical industry, a lucrative exporting sector run by the Islamic Revolutionary Guard Corps, which is now rightly listed by Washington as a terror organization.

America’s allies are eager to revive the smooth flow of goods and business with Iran; their diplomacy is meant to put pressure on Washington to start a process that would lead to new direct talks. Iran, they claim, will behave better, now that its economy is strained. America should take advantage and aim for a fresh rapprochement.

The problem with the allies’ theory: No such hunger for reconciliation is in evidence in Tehran. Instead, the regime is still signaling obstinacy. The ayatollahs are as committed as ever to their revolutionary principles, the main one of which is waging war on US interests and allies.

Take Foreign Minister Javad Zarif, long touted as a symbol of moderation and openness and a welcome guest in Western TV studios. Yet defending Iran’s habit of hanging gay people in the public square, Zarif told the German newspaper Bild this week: “Our society has moral principles, and according to these principles we live.”

Hosting Germany’s Maas this week, Zarif also pushed back against Secretary of State Mike Pompeo’s recent offer of negotiations “without preconditions.” The Islamic Republic won’t talk to those who wage “economic war” against it, Zarif said, threatening for good measure that, as an Iranian enemy, America “cannot expect to stay safe.”

The theocracy is hardening, rather than softening, its line, notwithstanding entreaties from Tokyo, Berlin and Brussels. These well-meaning outsiders inevitably point to supposed moderates that America can do business with, and, as always, they urge Washington to ignore Tehran’s malign rhetoric and muscle-flexing.

It’s true that some Iranian politicians favor making cosmetic concessions to the West to ensure the Islamic Republic’s survival. But the ultimate decider, Supreme Leader Ali Khamenei, has long soured on such concessions. Negotiation, he recently said, “has no benefit and carries harm.”

In a perfect world, the global economy would be better off when everyone can do business with everyone without fear of punishment. But the existence of a militantly anti-Western regime like Iran’s is a reminder that ours isn’t a perfect world.

Abe, then, would be better off warning Iran about its joint missile development with Japan’s menacing neighbor, North Korea (a reminder that the regime’s behavior is destructive far beyond its immediate neighborhood.)

Talks may be worthwhile — but not before Khamenei leaves the stage. Once the old dictator is gone, the ensuing internal struggle may work to the West’s advantage.

Economic pressure may then embolden Iranians hoping to throw off the regime’s yoke. Or it may not. Either way, dealing with the regime as it exists is futile, as more than four decades of experience have shown.

Trump should turn a deaf ear to Abe and the rest of the world’s eager go-betweens.

Twitter: @BennyAvni