To many in Europe and around the world, the American centre and centre-left can look chaotic: too broad, too noisy, too ideologically confused. The most useful shorthand is this: a moderate Democrat often resembles a European liberal, while a progressive Democrat often resembles a European social democrat.

The party’s moderate wing talks about competence, stability, the rule of law, democratic norms, and incremental reform. In European terms, this is the coalition of liberal constitutionalism: pro-democracy, socially tolerant, internationalist, but usually cautious about the state moving too far or too fast.

The progressive wing is more animated by economic inequality, class, race, labour power, housing, healthcare, climate, and the failures of neoliberalism. In European terms, this is often closer to social democracy: more redistributive, more sceptical of concentrated wealth, more willing to use the state, and more inclined to treat economic insecurity as the central moral and political fact.

That distinction matters because Democrats are now fighting on two fronts at once. One is cultural and institutional: how to defend liberal democracy against an increasingly illiberal right. The other is material: how to speak to voters who do not experience politics as a constitutional drama, but as a struggle to pay rent, buy groceries, afford healthcare, and imagine a stable future.

The 2025 elections showed that both wings of the coalition still had real political life. In Virginia and New Jersey, Abigail Spanberger and Mikie Sherrill decisively won gubernatorial races as candidates of competence, seriousness, democratic stability, and institutional normalcy. Their victories suggested that there remains a large constituency for a moderate Democratic politics that looks, to European eyes, a good deal like liberalism: reformist, professional, rights-conscious, and wary of ideological excess.

But 2025 also produced a very different kind of Democratic success. In New York City, Zohran Mamdani won the mayoralty as an openly left-wing figure. That result showed that the progressive, social-democratic current was not only alive but capable of mobilising voters around inequality, housing pressure, and disillusionment with establishment politics. Together, those three races made the core point of the period: the Democratic coalition was not resolving its internal tension by choosing one model and discarding the other. Both models were viable.

But one issue now threatens to sharpen these coalition tensions further: Israel, Gaza, and now the widening Iran war.

Even before the regional escalation, Israel and Gaza had already exposed a deep divide inside the Democratic coalition. Older, more institutional Democrats tended to be more pro-Israel, or at least more cautious, treating the issue through the language of alliance management, security, and political restraint. Younger progressives, many Arab American voters, and a wider activist left increasingly saw it through the language of human rights, genocide, apartheid, anti-colonialism, and international law.

That divide is not just moral or rhetorical. It increasingly shapes money and power inside the Democratic Party’s primaries. In Illinois this month, AIPAC-aligned outside groups spent roughly $22 million across the state’s major Democratic contests, with AIPAC-backed efforts posting mixed rather than dominant results. In Illinois’ 7th and 9th Districts, their candidates went down to defeat while winning in Illinois’ 8th and 2nd Districts. The point is not that pro-Israel money has ceased to matter. It plainly still does. The point is that its support is no longer the uncontested asset it once was inside Democratic politics.

The widening war with Iran raises the stakes because it turns a moral and geopolitical divide into an economic one. As oil markets react to the conflict, the political meaning of Middle East policy changes at home.

That matters politically because once war abroad feeds directly into petrol prices, food costs, and the costs of basic goods, the internal Democratic argument changes. It is no longer only about solidarity, morality, or the proper language of foreign policy. It becomes a domestic question: why should voters pay the price?

In this environment, Middle East entanglement begins to look not only morally corrosive but economically regressive. Unless there is major de-escalation, it could help define the political environment for this election cycle and the next, much as Iraq shaped the climate of 2006 and 2008.

Liberalism in the American centre-left survives less as a label and more as a governing instinct. But whether that instinct can lead the coalition will depend on whether moderate Democrats can show that democratic politics is capable not only of defending institutions, but materially improving the economic conditions of ordinary people.