The thing is a power struggle at the level that Santorum is talking about would play out like Santorum says. But such a power struggle would be a crisis such that we have never seen in this country. It would not really be about what the law and Constitution says; it would be truly about who has the real power. We (Americans today) can not think in the frame of reference for what Santorum is describing. It would appear truly abstract to us today.
Santorum is talking about a case where
–Congress passes “A”.
–The Court says “Not A, but B”.
–And the Congress responds with “We know you say B, but we’re gonna do A in spite of what you say”
–And the President in turn responds with “I know the The Courts says ‘Not A, but B’, but we’re gonna do A instead of B no matter what the Court says” and then signs whatever it is.
This would be more of a parliamentary supremacy (although not exactly the same) issue being made by Congress whereas the Court would be making more a divine right of kings (again not exactly the same) argument. And the President agreeing with the Congress would be more than enough power to carry the day.
In a situation like that the President and the Congress would win in the end. They actually have the command of boots on the ground and the support of the people respectively. If they cared enough and had numbers and support enough to feel safe about directly overruling the S.Court then they’ve already won and know it. If the Court didn’t blink first (in such a situation the Court would in fact blink) then the necessary impeachments or statements of the supremacy of law would follow.