[openasocket]

> and that laws should take an 80% consensus to pass.

I think this is trying to solve the wrong problem. If our concern was that the second the new party gets that 51% margin they suddenly start passing a ton of laws, that would help reign it in. But that's not really what is happening. Congress has become profoundly unproductive in the last few decades. As an example, the last time Congress passed a budget on time, which is the bare minimum of functioning, was in the 1990s. By basically any metric, Congress is becoming less and less capable of passing laws. Requiring 80% consensus would make that even harder. And requiring laws to be reviewed every X years would greatly increase the responsibilities of Congress to keep the government functioning.

[somenameforme]

It's more about the equilibrium and motivations that this system creates. When everything is decided on a 1% majority, there's no real need to cooperate on anything. If you don't have power now, you probably will in a few years and then you can do whatever you want. So you can just focus on getting reelected in the mean time and vote no on everything until then. This, btw, is exactly what happens - Congress spends most of their time in office simply working on their next election. Term limits would seriously help here.

What you mention about budgets is a good example of this. Neither side wants to cooperate on anything at all. So in the House you get things like one side votes 100% yes, the other side 100% no. And then it gets passed to the Senate. The reason budgets freeze up in the Senate is the filibuster where you need a 60% majority to pass. So suddenly there's actually some cooperation required which is when both sides tend to start working together, a little, to add this or remove that.

But with an 80% consensus required, you need to start the cooperation immediately in the House because you can't just roughshod your fantasy budget through on a 1% margin. And none of this is going to change in 4 years, or 40. If you want to get things done, you need to start viewing 'the other side' as just other people working towards what they see as a desirable direction for the country, instead of an opposing team to be conquered and strawmanned into the worst evil since Hitler.