If I had to put a finger on when today’s extreme, identity-driven partisanship began (not just intensified), I’d say the early–mid 1990s, with roots a bit earlier and a hard lock-in after 2008.

Here’s how I see the phases.

1. The prehistory: cracks before the break (late 1960s–1980s)

Even during the era you’re implicitly contrasting with today, things weren’t as cozy as nostalgia suggests.

Civil Rights and Vietnam shattered the old New Deal coalition.

Southern conservatives slowly migrated to the GOP.

Ideological sorting began: liberals increasingly became Democrats, conservatives Republicans.

Still, cross-party coalitions remained normal. That’s why Ronald Reagan could cut deals with Tip O’Neill, and why Congress still worked like a bargaining institution rather than a trench system.

This was polarization without total delegitimation.

2. The real rupture: Gingrich and the weaponization of politics (1994)

The true inflection point, in my view, is the Gingrich Revolution.

Newt Gingrich did something new and decisive:

He framed Democrats not as opponents, but as corrupt, illegitimate, and immoral.

He nationalized congressional elections.

He taught Republicans to treat compromise as betrayal.

This wasn’t just sharper rhetoric — it was a new moral psychology of politics.

Once that happened, trust collapsed. And once trust collapses, institutions can still function — but only mechanically, not cooperatively.

3. The Supreme Court as early warning signal (1990s–2006)

Your judicial examples are especially telling, because the Court used to be insulated from partisan warfare.

Ruth Bader Ginsburg (1993): 96–3
→ last gasp of bipartisan legitimacy.

John Roberts (2005): 78–22
→ polarization clearly underway, but norms still restraining it.

Samuel Alito (2006): 58–42
→ near party-line vote; the dam is cracking.

By Alito, confirmations had become proxy wars over the future of the country, not evaluations of legal competence.

That shift is irreversible once it starts.

4. 2008–2010: polarization becomes existential

I agree with you that by 2008, across-the-aisle collaboration was basically gone — but I’d add why.

Two things converged:

Barack Obama
His election activated racial, cultural, and identity-based backlash that had been latent.

Strategic obstruction
Senate Republicans (openly) concluded that total resistance was electorally advantageous.

At that point, politics stopped being about policy disagreement and became about preventing the other side from governing at all.

That’s not polarization anymore — that’s mutual delegitimation.

5. Why it feels categorically worse now

Earlier eras had:

Ideological disagreement

Hardball tactics

Bitter rhetoric

What’s different now is:

Zero shared epistemic reality

Moralized hatred of the opposing party’s voters

Politics as identity rather than instrument

Once parties stop believing the other side has a right to rule, collaboration becomes psychologically impossible — not just politically inconvenient.

Bottom line (my opinion)

If I had to date it cleanly:

Roots: late 1960s–1980s (sorting and resentment)

Birth of modern partisanship: 1994 (Gingrich)

Institutional collapse of norms: 2005–2006 (Roberts → Alito)

Full hardening into today’s system: 2008–2010

After that, we’re no longer watching a malfunctioning democracy — we’re watching two rival moral communities sharing one constitutional shell.

Reagan opened the door to let the wolves into the sheep. Since then it has been a steady retreat on the part of Democracy. However, a critical error was made at the time of the post civil war organisation with the allocation of electoral college votes favouring the South. And if I can work that out from here on the other side of the planet, why cant Americans??😷

Of course there was no one clear moment, but I think the closest thing we have is Newt Gingrich encouraging Republicans to call their opponents "sick" and "evil" while continually moving Right, and calling the Democrats "too far Left" even as they keep moving to the Right to try meeting the Republicans halfway. Gingrich understood the weakness of Liberalism. Liberals are institutionalist, which Gingrich was able to exploit.

Another big moment in more recent years was the 4chan forum /pol/ which normalized Nihilist Fascism on the internet. We now know that Epstein was behind /pol/ which is both horrible and hilarious.

I'm not sure you can put a finger on a precise date. But I would say it most likely was during the Clinton Administration: on the one hand he recognized it was "the economy, stupid", actually balancing the budget towards the end of his administration, creating the NAFTA free-trade market stealing two of the Republicans long-standing issues while, at the same time, being caught up in moral issues with Monica that riled the Evangelicals and brought the Mega churches into MAGA politics. Cemented further when Gore vs Bush to succeed him led to the first claims of an election being stolen.

Personally I think it really became “us versus them” somewhere in the Kennedy election then worse when bill Clinton got impeached for not pleading the 5th. Bush is when it got seriously divided.
If only gore had pardoned bill clinton?

In 1994 when Newt Gingrich and the GOP took over the House and started going after Bill Clinton.

Let's try around the mid to late 1600s...

in the 1700s.

St Ronnie Ray-gun did a lot. But Newt Gingrich took it to a whole new level of "destroy the evil satanic Democrats who eat babies and force kids to get sex change operations."

That later morphed into MAGA and trump.

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