> I often wonder how many problems could have been avoided if we required 2/3 majority.

California used, until recently, to have such a supermajority requirement for the budget—not all legislation, just the one piece of legislation that is an annual must-pass.

It was the primary source of perennial budget crisis, and, it let a unified minority party that held it's unity (usually Republicans, because they usually were in the minority and almost always more unified in the state than Democrats) to dictate terms so long as they were more willing than the majority to hold the state hostage.

Plus, conversely, it also makes the majority party less accountable, because they can always blame the intransigence of the minority and the disastrous consequences of not reaching some deal for the actual contents of whatever deal is reached. A supermajority doesn't mean everyone owns the results, it means no one does.

Few of our pathologies can be solved piecemeal.

Consensus would be nice in a less polarized, partisan context.

The primary driver for our partisanship is our winner-takes-all form of elections. Switching to approval voting for executive (one position) races and proportional representation of assemblies (house, councils) would dramatically reduce partisanship. Which would maybe then enable more consensus driven governance.

One can hope.

That is the case for some legislation, such as when is necessary to override a presidential veto. Requiring it for all legislation would pretty much lead to a standstill, or worse - peddling to the special interests of a small coalition (this is my opinion).