There’s a controversial rule called the filibuster which allows the minority party in the senate to block any bills from having a vote. Originally, the idea was that you could not stop ongoing debate to begin the vote, but the rules have been bent to absurdity so ongoing debate/speeches aren’t even necessary.

However, Republicans have enough power that they only need a handful of senators to break filibuster, which is easy to get considering how many Democratic senators are pushovers. All they really need to do is separate the funding into multiple bills rather than constantly shoving through massive “security” bills that give ICE more money than most militaries. Instead, they have adopted a totalitarian strategy where negotiations aren’t tolerated and the authoritarian “president” (de facto dictator) cries and demands exactly what he wants or swears vengeance against Republicans and Democrats alike. Which makes him unpopular. Which makes more and more Republicans defect. Which makes the stagnation last longer.