Like New Yorkers, Iranians were out on the streets over New Year’s — except rather than braving ever-dropping temperatures, they faced tear gas, nasty riot cops and bullets.

Think we’ve seen this before? Wrong.

The ongoing days of rage (five and counting) are remarkably different than the failed protest in the aftermath of the rigged 2009 Iranian election.

They may signal the start of an evil regime’s downfall and reshape the entire Mideast.

But Iranians need our help.

The 2009 Green Revolution started after the rigged re-election of then-President Mahmoud Ahmadinejad. His regime’s rivals led street protests in Tehran. They spread beyond the capital and eventually petered out, quashed by thuggish regime enforcers.

This one’s leaderless. It started late last week in remote towns like Mashad and Rasht and only later spread to the capital, rooted in the poorer economic enclaves and spreading to the higher classes via Instagram, Telegram and other social media.

Demands are much more far-reaching. Rather than seeking to replace one clerical leader with another, these protesters want to scrap the whole system.

They chant, “No Syria, no Gaza, we’d die only for Iran.” And “Reformists, traditionalists, you’re all the same.” Even “Down with the dictator,” accompanied by the destruction of posters of Supreme Leader Ali Khamenei.

This, in other words, is about regime change.

And there’s another crucial difference between 2009 and today. Back then, President Barack Obama was secretly planning to launch talks with the regime. When the Green Revolution threatened to undermine his overtures, he mostly stayed mum.

And guess what? Over the weekend Philip Gordon, an architect of Obama’s Mideast policies, wrote in a widely echoed op-ed we should “do nothing” now, too.

His argument: Iran’s leaders would claim a US-Zionist plot. Let’s exercise some humility. This is about Iranians, not us.

Yet, Cold War dissidents like Natan Sharansky say President Ronald Reagan’s encouragement helped them survive the Soviet regime. Now as the veteran Farsi-language broadcaster Menashe Amir tells me, the current uprising needs international, and specifically American, encouragement to survive the regime’s onslaught.

According to the regime, at least a dozen demonstrators were killed so far. Scenes of beatings and tear gas widely spread on social media, while the regime shuts down Web sites and services.

This time, administration officials and congressional leaders, including Democrats, immediately publicly supported the protestors’ rights, and warned the regime that “the world is watching,” as President Trump tweeted in an uncharacteristic measured tone. (Even Hillary Clinton chimed in on the protesters’ behalf.)

Iranian President Hassan Rouhani protested that Trump, “who is against the Iranian nation from his toe to his brain, has no right to pretend sympathy with Iranians.”

But in the streets, few still equate the regime with the people. Also gone is a distinction, so enamored by America’s Iran experts, between “reformists” like Rouhani and “hardliners.”

Rouhani has promised huge economic benefits from Obama’s nuclear deal. Corporations greedily rushed to Iran once sanctions were lifted, but only the elites, like the Revolutionary Guard Corps, who control much of the economy, were enriched.

Meanwhile, prices of basic commodities keep rising. Dissenters are hanged or imprisoned. Women are forced to wear the veil. Corruption is rampant.

Unemployment in some sectors nears 40 percent. And the country defiantly builds missiles and lavishes funds on Syria’s Assad, Hezbollah, the Houthis and other “resistance” groups.

Do nothing? Absurd. America should amp-up encouragement to protesters. Europeans, so quick to jump on any human-rights bandwagon but decisively quiet about the rights of Iranians, should be shamed into joining in.

And this is no time for a regime lifesaver. Rather than ease sanctions, America should reiterate to Europeans, Asians and others that they can either do business with the clerical oppressors or with us, but not both.

Regime change has always been our best option for dealing with Iran’s America-hating genocidal dictators bent on possessing nuclear weapons.

Rather than doing nothing, we should side with those in Iran who share that goal.

The Islamic Republic may not fall tomorrow, but as in the Cold War, oppressive regimes rarely last forever no matter how stable they look to outsiders.

And just like then, we have an important role as catalyst in their demise.