Policies have institutional inertia. International accords can be broken, numerous polluting plants and pipelines built, and irreversible environmental damage can be done in four years. It's a matter of rolling back the effects of the policies that may take decades (or never, if the environment is pushed past the point of no return).

The danger of a supermajority in COTUS, POTUS and SCOTUS is alt-right and Freedom Party extremist agendas being railroaded through and ripping up sensible, sane policies into tatters for those special interest$ and crazy fringe groups.

Two healthy political parties provide countervailing powers which limit what the other can do. Without this protection, fascist themes become more prevalent and more difficult to stop.

Did you mean to reply to the parent comment rather than mine? It seems more relevant:)

How long does it take to break a window? How long does it take to replace that window?

Destruction and creation are asymmetrical with respect to the time and effort required to do either, and that's not even looking at immaterial stuff such as international reputations and treaties.

You act like agencies and experts can be rebuilt and rehired as quickly as they were dismissed. That isn't true of anything I can think of.