Since Lindsey Graham has a complete reversal of opinion between 2015 and 2018. it would be naive to think that he was not influenced in some way by Trump.
The New York Times article from 2 days ago provides the best answer.
Graham is running for re-election for a 4th senate term in a state where Trump has high approval ratings. That's really all that you need to know.
Trump's approval rating with South Carolina Republicans is more than 80%. The state is considering not having a Republican primary in 2020 to help him:
Bezos under attack by far left wing people-Cortez.