Congress can override them.
You'd think, with a repub majority, they could override anything they'd consider too far... but they don't.
It can also be struck down by the courts.. and they aren't.
Larger policies also require approval to go through from the judicial branch.
It's far from "yeah, the president says and so be it!". That people aren't using the balances provided either means that they're not actually something they care about or they're not unconstitutional.