[Lucas the Private Eye]

Seems like “the term for which he was elected” is pretty easy to understand. You can’t just opt out by resigning.

But in the end, does it really matter? Has the US Constitution really driven much of anything of late?

[Dimples]

It only matters if you (we) care to make it matter. And yes, though under attack on many fronts, the Constitution is still the governing authority of the US of A. Its erosion can be traced to precisely the attitude your question implies: "Why bother?"

In the end, it does matter. Win or lose, not asking the question, or not engaging in the debate makes the outcome assured: you'll lose every time!