Welcome to Mamdanistan.

On Tuesday night, America’s most important city became a beachhead for the black-red alliance. This is the combination of Islamism and ultra-leftism, embodied by New York’s mayor, Zohran Mamdani, that has the whole of America in its sights.

Three Mamdani-backed extremists defeated establishment candidates in New York’s Democratic House primary.

Two of them, Claire Valdez and Daraliza Avila Chevalier, are affiliated to the ultra-left, anti-American Democratic Socialists of America. If elections to New York’s legislature are included, seven out of eight DSA-affiliated candidates won victory this week.

In addition, Rep. Dan Goldman was beaten in the city’s 10th Congressional district by his fellow Jew Brad Lander, a slavish Mamdani ally who has groveled to Islamists while demonizing Israel.

On social media, Chevalier has boasted of having “wiped my hand on the American flag.”

Chevalier, a convert to Islam, has called for the abolition of police, prisons and the country’s borders. She also co-founded Columbia University Apartheid Divest, a Muslim Brotherhood front group whose goals are the “full eradication of Western civilization” and the cultivation of “unrest and violence in America.”

All three candidates made ending American support for Israel a centerpiece of their campaigns. All three used the “genocide” libel against the Jewish state. Chevalier has doubled down on the support she voiced for Hamas the day after the terrorist group led the attack against Israel on Oct. 7.

For his part, Mamdani referred last week to the pro-Israel lobby group AIPAC and its supporters as “monsters,” channeling the key antisemitic conspiracy theory that accuses the Jews of controlling America in the pursuit of diabolical goals.

The ultra-conservative Islamists and the ultra-progressive leftists are united in two main things that drive them: their desire to end America and the west, and their deranged loathing of Israel and the Jewish people.

This loathing isn’t just the glue binding them together. It’s the Islamists’ key weapon against America itself.

The “Jewish question” is now turning into the driver of Democratic party politics. Hatred of Israel is a Trojan horse for the agenda of Islamization, the process of conquering America and the west for Islam.

For decades, we’ve watched this story playing out in Britain, where it’s rapidly reaching the point of no return.

Although many British Muslims sign up to the country’s core values, a huge number demand instead that Britain adapts to Islam.

Following the Muslim Brotherhood playbook, Islamic radicals have patiently infiltrated and subverted British politics and culture.

Although Muslims officially account for only about 6% of the population, they’ve achieved critical mass in certain cities and towns. This has enabled them to make disproportionate inroads through the democratic process for a specifically Islamic agenda.

Accordingly, Britain is now gazing aghast at the emergence of a rapidly growing sectarian Islamic caucus, with MPs and other public officials standing on a platform of “Gaza first” and with the issues of Israel and Zionism now absurdly driving British politics.

And close behind that is the demand that core western values, such as freedom of speech, must give way to the demands of Islam.

A similar process is under way in America. New York’s Muslims are now equal in number to the city’s Jews.

Red-black extremists are now threatening establishment candidates in Colorado, Michigan and Wisconsin, while another radical leftist is poised to become mayor of Washington DC.

This process will metastasize even further very fast. Galvanized by the October 7 attacks and the way western elites subsequently turned against Israel, the Islamists believe they’re on the cusp of victory over America and its allies.

While their motivation has gone through the roof, their useful idiots in the West’s liberal establishment are refusing to see what’s staring them in the face. Instead, they’re obsessively sticking pins into effigies of Donald Trump, while acting as an echo chamber for the Islamists’ lies painting Israel as a demonic force in the world.

Although New York’s voters may nod along to these lies, most of them hardly rank Israel as of greater concern than things like the cost of living.

But Israel stands proxy for something else: a state that the public believe is grinding the faces of the poor and disadvantaged. Just like them. So a vote for those who hate “oppressive” Israel appears to them as a vote for the “oppressed” everywhere.

The Democrats imagine that they’re using the Islamists to promote left-wing policies. The truth is that the Islamists are using the Democratic party to turn the US into Ameristan.

People don’t take this seriously because they can’t believe it could ever happen to mighty America.

Look at Britain and believe it. This is how the western frog is being boiled slowly in the pot.

Melanie Phillips is the author of “Fighting the Hate: A Handbook for Jews Under Siege” (Wicked Son).