The expansion of executive powers us usually makes sense to the party in power, and doesn’t make sense to the minority party. But there was always an understanding that everyone was a rational actor with these powers. No one ever stopped and asked what would happen if someone a little more irrational now had these expanded powers.
No, the judicial and legislative branches have ceded it. The whole point of checks and balances is the tacit understanding that each branch will naturally grow as much power as it can and it is the responsibility of the other branches to check it.
Blaming the executive branch for growing its power is like blaming the seller for high prices in a free market — the system is designed presuming competition and selfish behavior.
Frankly, I think we should be impressed. It's a borderline miracle that it's survived as well as it has.
Actually they did. The Federalist papers contained some strong warnings that we must strive to prevent factions / parties from taking over. They were painfully aware it was a potential failure mode in the system they were designing.
It also robs the US of a signalling mechanism: there's no way for the Republicans or Democrats to see that they didn't get primary vote share and only recovered it after specific-issue or more focused parties dropped out.
The US desperately needs preferential voting and mandatory voting. The default supposition of the US has to be that there must be exceptional circumstances as to why any individual did not vote.