'These people aren't trying to persuade the party, they're trying to hijack it, slap a rose emoji on the wreckage and call it a movement,' one top Democratic strategist told me after democratic socialists beat two incumbents in House primary races in New York City on Tuesday.

To say that party moderates are in a tizzy is a vast understatement.

Overall, three allies of New York City Mayor Zohran Mamdani triumphed over establishment-backed candidates in a political earthquake that will be analyzed for months, perhaps years. But while some political operators, such as New York Attorney General Letita James (who suggested Mamdani is 'blowing up' the party) are sounding the alarm, leadership in Washington isn't saying much.

Since Tuesday, Democratic leaders Chuck Schumer and Hakeem Jeffries have dodged questions about the socialists who are almost certain to become their colleagues in the next Congress. Privately, though, Democratic House members and many of the party's strategists and donors that I talk to are aghast.

'Democrats have a DSA problem, and pretending otherwise is political malpractice,' said the strategist, who has been part of top-level party conversations for years. 'The DSA (Democratic Socialists of America) crowd has mastered the politics of performance art: promise everything, explain nothing, scream "establishment" when questioned and hope nobody asks who pays the bill,' they said.

'It's fantasy math, a dangerous public-safety agenda and too often stoking antisemitism wrapped in moral superiority. They are driving the party further away from the American people – and if they succeed, they could set the Democratic Party back decades.'

Some observers, including me, saw this coming. For years, many leaders of the Democratic Party treated Senator Bernie Sanders as a sideshow, a historical detour, rather than a thoroughfare for acolytes. That has always struck me as a mistake.

Whether one believes Sanders would have won the Democratic presidential primary when he ran in 2016 or 2020 – absent the ruthless, coordinated efforts of Democratic party leaders to organize against him – is, of course, a matter of fierce debate.

What is beyond dispute is that an independent senator from Vermont, who proudly calls himself a democratic socialist, came remarkably close to capturing the nomination. Twice. That should have prompted far more soul-searching inside Democratic circles than it did. 

Instead, many establishment Democrats seemed relieved to have simply survived and the result was that the party never fully grappled with the forces that propelled Sanders from curiosity to contender. Those forces have not disappeared. If anything, they have only appealed to younger, angrier, more purposeful and more digitally connected candidates and voters, in New York City and beyond.

There is an echo here of what happened to the Republican Party a decade ago.

Long before Donald Trump descended the golden escalator, there were warning signs that their voters were straying from the establishment stable.

A longtime Republican strategist and adviser, Pat Buchanan's insurgent presidential campaigns (in 1992 and 1996) exposed a restless populist streak inside the Republican tent. Libertarian Congressman Ron Paul's devoted following demonstrated the power of an outsider movement fueled by voters who believed the establishment no longer represented them. But Republican leaders largely dismissed both men.

Then a brash, New York real estate mogul arrived – and the elites largely ignored him too.

After Trump spoke at the Conservative Political Action Committee's annual conference in 2011, I went on national television and shocked many in the commentariat when I said, you may not take him seriously, but take his idea seriously because they have a lot of resonance with the American people.

Indeed, they did. Trump turned what seemed like isolated mutinies into a wholesale takeover of the party.

Now, Democrats are not Republicans and Mamdani certainly is not Trump. The consortiums, ideologies and personalities are entirely different. But there is a comparable question confronting Democratic leaders today: Have they dangerously underestimated the depth of dissatisfaction inside their own coalition?

Mamdani and his allies campaigned not only against individual opponents but against institutions. They challenged the party establishment represented by Schumer and Jeffries. They attacked the city's political status quo. They made opposition to Israel's conduct in Gaza a central issue. They sharply criticized Immigration and Customs Enforcement. And they took direct aim at AIPAC – the American Israel Public Affairs Committee – the influential advocacy organization that has become an increasingly prominent player in Democratic primaries.

Some observers will conclude that Israel was the defining issue behind these victories. Others will argue it was simply one element of a broader anti-establishment mood driven by rising housing costs, declining affordability and generational change. Untangling those motivations will take time, but the wheels have been set in motion.

A democratic socialist is on track to become the next mayor of Washington, DC. The next major test may come in Michigan, where the Democratic Senate primary in August features a candidate whose issue positions are quite like Mamdani's. And national Republicans are likely to spend the next year trying to tie their opponents to the Democratic Socialists of America platform on positions like immigration (abolish ICE), law enforcement (defund the police), economic policy (Green New Deal) and foreign affairs (global solidarity).

Then there is Mayor Mamdani himself. Winning a primary is one thing. Converting a political movement into effective governance is something else entirely. How he uses his newfound influence and whether he can broaden his appeal beyond the activist base that powered his rise will shape not only his own future but the direction of progressive politics nationally.

Just as important will be the response from Democratic leadership. Leaders Schumer and Jeffries now face the delicate task of holding together a coalition whose ideological divisions have become increasingly difficult to downplay. Their public posture – and their private strategy – will reveal a great deal about whether they believe Tuesday's results represent an isolated phenomenon or the leading edge of something much larger.

One other political player also finds itself at an inflection point. AIPAC has spent enormous sums trying to shape Democratic primaries over the past several election cycles. The rise of anti-Israel Democrats will inevitably spark a debate inside the organization and among its allies about whether its current strategy remains the most effective one or whether AIPAC has, in some races, inadvertently strengthened the very narrative and forces that they are trying to defeat.

Every Democrat considering running for president in 2028 will have to grapple with how to balance confrontation and accommodation with the energized and activist wing of the party.

Republicans once dismissed the insurgency growing inside their party until it was too late.

As they say, history rarely repeats itself exactly, but it often rhymes.