The Northeast is well-known terrain to the American media, and in political terms it's known above all else for being liberal. But when the Republican primary turned to New York last week, it delivered Trump his best state yet. He followed that up this evening with romps in Pennsylvania, Maryland, and Connecticut.
The only majority he's gotten so far came from New York — not Alabama or Mississippi — and the very Trumpiest country in the country so far is Staten Island, an affluent, leafy, fundamentally prosperous and suburban section of the northeastern megalopolis. This region of the country isn't very friendly to Republicans, and Trump won't carry it in November, but for the purposes of a GOP primary it's his promised land.
In past cycles, the Northeast has served as a stronghold of moderate Republicanism — checking the advance of pure conservative true-believer candidates and helping deliver the nomination to relatively electable mainstream alternatives.
Northeastern politics is about group conflict
There are two fundamental ways to look at politics.
To some people, politics is ideological — it's about big ideas, big issues, and big principles.
To others, politics is about group conflict — it's about who you stand with, and who you stand against.
Everyone feels the tug of both of these ideas, and every successful political movement incorporates a little of both. But the modern Republican Party as a whole has become a very ideological organization. Trump is, fundamentally, a backlash to that.
Huge swathes of white working-class America have moved into the GOP orbit because they see the modern Democratic Party as fundamentally not for "people like them." Many of these voters aren't particularly interested in the details of the conservative agenda, and have no principled opposition to programs (like Social Security) that they see as benefitting them personally. What they want is a politician who'll stand up for their interests, not a politician who adheres to a particular ideology.
But it's also the Northeast. On the Pacific Coast, state Republican Parties have generally clung to conservative ideology and simply contented themselves to be outvoted in statewide races. The Northeast is different. Massachusetts, New Jersey, and Maryland all currently have Republican governors. George Pataki served three terms as governor of New York, and New City recently had a 20-year run of Republican mayors.
These politicians were (and are) pretty different from one another, but in that diversity there is a common theme: a fair amount of ideological flexibility that allowed them to build majority coalitions of white people prepared to stand against domination of state politics by "urban" machines.
This is Trump's basic brand of politics. You may not know exactly what he stands for, but you do know exactly who he stands for — or at least who he stands against.
Racial resentment is high in the Northeast
The South, which has already voted, is Trump's second-best region. And in most economic and political indicators, the South and the Northeast are opposite ends of a spectrum.
But one important area in which they are kissing cousins is white racism.
Here's a map from Harvard's Project Implicit showing the average score of white test-takers on a test of implicit racial bias.
On this map, New Jersey might as well be part of the Deep South.
And even this understates the centrality of racial resentment to Republican Party primaries in the Northeast. The South, unlike the Northeast, contains lots of churchgoing white evangelicals with deeply felt conservative ideology — Ted Cruz voters, in other words. And the Northeast, unlike the South, contains lots of highly ideological white liberals who deeply despise the Republican Party — Bernie Sanders voters, in other words.
This leaves Northeastern Republican Parties full of not-super-ideological people who just really don't like the Democratic Party because they don't think it stands for people like them. That's perfect Trump terrain.
Why Trump's northeastern domination matters
Southern niche candidates have emerged in GOP primaries before and lost — think Mike Huckabee in 2008.
We've even had in Rick Santorum's 2012 campaign a non-Southern evangelical Christian who did well in the South and also expanded his appeal a bit into the Rust Belt.
But in both of those races, the establishment favorite was ultimately powered to victory in part thanks to strength in the Northeast. The Northeast's less-ideological Republicans didn't care about the past heterodoxies of John McCain or Mitt Romney and helped power more electable, more mainstream choices to the fore.
Trump, by foregrounding racial resentment in a way no candidate has done since George Wallace, is blowing that calculation up — and the Republican Party with it.