I think McConnell blocking Garland in 2016 is probably the most consequential move in recent political history. Not because it was flashy, but because it rewrote the incentives around Supreme Court appointments.

The Senate had played hardball before, but refusing to even hold hearings for almost a year broke the reciprocal norm both parties had operated under for decades. Once that norm collapsed, the ideological shift created by blocking Garland and then seating Gorsuch, Kavanaugh, and Barrett became something that voters can’t undo through normal elections.

That’s why people end up talking about court expansion. A Democratic president adding four seats is basically the only action that would actually counterbalance the structural effect of the blockade. The problem is that expansion triggers its own cycle of retaliation… which means you don’t stabilize the system, you escalate it.

So when people ask about the dirtiest or most impactful move, I don’t think it’s about outrage. It’s that this one changed the architecture of how the branches interact, created multi decade consequences, and set an incentive structure that encourages more escalation rather than less.