A moral constitution does not literally translate to apply only to moral issues. It is having an internal guide on right and wrong, a point at which your moral constitution recognizes I do not compromise on this no matter the financial or political benefit to me. I hope that clarifies my point for you.
So if your concern over position changes for moral constitution issues causes you to have issue with Cruz on H1-B visa numbers, does it cause you to have issue with Trump on abortion at all? How about socialized medicine?