Thomas Jefferson to Abigail Smith Adams,
Monticello, Sep 11, '04.
"You seem to think it devolved on the judges to decide on the validity of the sedition law. But nothing in the Constitution has given them a right to decide for the Executive, more than to the Executive to decide for them. Both magistracies are equally independent in the sphere of action assigned to them. The judges, believing the law constitutional, had a right to pass a sentence of fine and imprisonment; because that power was placed in their hands by the Constitution. But the Executive, believing the law to be unconstitutional, was bound to remit the execution of it; because that power has been confided to him by the Constitution. That instrument meant that its co-ordinate branches should be cheeks on each other. But the opinion which gives to the judges the right to decide what laws are constitutional, and what not, not only for themselves in their own sphere of action, but for the Legislature & Executive also, in their spheres, would make the judiciary a despotic branch."
Also, the President could get around any of this by just issuing a pardon to anyone convicted of a section of any law that he feels is unconstitutional.
It really is THE question though. Who decides? We've had nullification problems before, because all possible means seem to invite chaos. Can the president nullify a law he thinks is unconstitutional? Then how about states? Jefferson felt they could as well. So how to operate as a Union if some states recognize a law other states nullify? Or if a president nullifies a law that all states recognize? etc. Seems to me America has settled on the SCOTUS being the final arbiter, Jefferson's admonition notwithstanding. Seems to me we fought a war over a lot of these issues as well.