Well, I agree that Graham’s stance on immigration is more moderate than Trump’s regarding amnesty, and he doesn’t deny that. But on enforcement, the wall, catch and release, etc. he’s siding with the President.
As far as the rest, I think people under estimate the effect of coercion, bribery and blackmail as the basis for many of the alliances in Washington. The swamp creatures try to convince the public that their positions on a particular issue are based on principle when in reality the truth is much uglier. Many of the worst political alliances in Washington are kept together by threats, bribery and other forms of crimminalty. I believe Graham was in some sense controlled by McCain in the past and that their alliance had a lot less to do with genuine agreement on the issues. Since McCain left the scene, things have changed for Graham.
If Graham is re-elected he will be telling everyone that the voters who voted for him voted for amnesty.