And before anyone says "but the US only has adversarial courts" - well, the US had a secret spy court for more than a decade that rubberstamped anything the NSA/FBI requested, and it didn't seem to be an issue until the Snowden documents leaked and there was major backlash against it.
But honestly, a Constitutional Court is what the US needs right now. Something to stop the insanity of politicians in the mid-term.
Long-term, you stop their insanity by actually preventing them from getting elected in the first place. You do that by getting rid of money in politics, the FPTP voting system that promotes party a 2-party system and extreme polarization, and gerrymandering (a proportional representation voting system would fix both of the last 2 issues).