Sen. Lindsey O. Graham (R-S.C.) on Wednesday offered his most extensive comments to date about President Trump’s continued attacks on his friend, the late senator John McCain (R-Ariz.).

And it’s a great window into the codependent relationship Trump has forged with GOP lawmakers like Graham.

Graham’s lack of a more forceful defense of McCain has been criticized, even as he has gradually weighed in more. He even copped this week to his own role in McCain turning over the Steele dossier to the FBI — the initial source of Trump’s latest McCain onslaught.

But Graham also explained to CNN that he wasn’t minding his critics because he felt they were just using him to make Trump look bad. “If you think the only way to honor John McCain is to tell this president, ‘I won’t work with you; I won’t ever help you,’ ” Graham said, “that’s your agenda, not mine."

And then came the big quote.

“President Trump has been good to me in the sense that he’s allowed me in his world,” Graham said. “He’s made decisions, I think, based on some input I’ve given him. He’s subject to changing his mind, and I want him to be successful.”

That first part is key — the part about how Trump has been “good to me” and “allowed me in his world.” Graham isn’t just any senator, you see; he’s the chairman of the powerful Senate Judiciary Committee. He’s one of the most potent people in what is supposed to be a coequal branch of government. Yet he’s suggesting Trump has done him an important favor by accepting his guidance.

It’s tantamount to admitting that Trump holds the cards in this relationship — which he clearly does. Graham rather obviously didn’t like Trump, calling him crazy and unqualified during the 2016 campaign. Graham has since pulled perhaps the most stunning 180 in Washington, becoming a close Trump ally and confidant. He has admitted this is in large part about his own political future; he’s up for reelection in 2020, and the threat of a primary challenge was always very real.

And Graham’s conversion has paid off. After turning himself into the designated GOP attack dog during Supreme Court hearings on Brett M. Kavanaugh’s Supreme Court nomination and sidling up to Trump, a recent Winthrop University poll showed Graham’s approval rating among South Carolina Republicans rising from 51 percent in April 2018 to 74 percent less than a year later. Graham isn’t stupid, and he has shown that his gambit — no matter how transparent — has worked.

But it has also come at the cost of some pride. Graham suggests that it’s not worth giving Trump ultimatums, because he needs something from Trump. But Trump also needs something from congressional Republicans. They have controlled the fate of his legislative agenda. Graham showed what he can do for Trump during the Kavanaugh hearings. Graham’s approval still lends legitimacy to Trump, because he was such a vocal critic one day and he’s a leading GOP voice on both judicial issues and foreign policy — and especially the latter now that McCain is gone.

What Graham is really saying isn’t that he doesn’t want to get tough on Trump, but that he can’t. Graham is admitting defeat in the face of a GOP base that abhors the kind of Trump critic he once was. Trump has built this kind of loyalty among congressional Republicans by punishing those critics with an iron fist and rewarding those who lavish him with praise — oftentimes by letting them be influential.

The result is powerful senators like Graham apparently believing it’s a privilege to be “in his world,” rather than emphasizing the role they play a legislative branch that is meant to be a check on the executive.