May declare executive actions unconstitutional

The correct answer is the judicial branch.

The Judicial branch has the authority, under the doctrine of judicial review, to review Executive action after a suit has been brought and to determine whether or not the executive branch has acted within the scope defined by the US Constitution.

well that depends on how deep the hole is. you'd first go through te crust of the earth, then the upper mantle, then the lower mantle then the outer core, then the inner cor then you'd be stuck in the core to melt.