I believe it works the other way; I think the Constitution authorizes Congress to do certain things as opposed to restricting them from what they can't do. In other words, if the authorization isn't spelled out in the Constitution, Congress can't do it. They cannot just do anything they think of merely because those things aren't restricted.
Otherwise, their power would be pretty much unlimited.
OTOH, the situation is the opposite for us citizens, we can do anything that is not restricted. Because, again, if we could only do whatever Congress, in it's wisdom, dreamed up to put on a list of permitted actions by citizens, our freedom would be damned restricted.
Instead, government power is pretty damned restricted. Or is supposed to be.
However, it does look to me as if the 14th would allow Congress to become involved in this case by taking the position that Terri has not received due process.
"I believe it works the other way; I think the Constitution authorizes Congress to do certain things as opposed to restricting them from what they can't do. In other words, if the authorization isn't spelled out in the Constitution, Congress can't do it. They cannot just do anything they think of merely because those things aren't restricted. "
Isn't this the argument made in the "Federalist Papers?"