President Trump’s main antagonist in the Republican Party has died, and there is no pining by Trump. The Washington Post’s Josh Dawsey reports that Trump nixed releasing an official White House statement honoring Sen. John McCain after the Arizona senator died Saturday. Instead, Trump sent out a much shorter and symbolically less-meaningful tweet.

If we put ourselves in Trump’s shoes — where unquestioning loyalty to him is the biggest determinant of being in his good graces — it’s not hard to see why the president didn’t like McCain.

In the last year of his life, McCain willingly molded himself as the keeper of the flame of what he believed was the true Republican Party. To McCain, that party was everything that Trump was not, and McCain seemed to feel it was his duty to be extremely vocal about that.

After Trump was inaugurated, McCain challenged the president on everything from his Cabinet picks to the president’s governing philosophy to Trump’s personal qualifications to lead the nation. McCain derided Trump’s foreign policy as “half-baked spurious nationalism” and urged Americans to “fight” against his “crackpot conspiracy theories."

He urged his Senate colleagues to remember that they are “not his subordinates.” He was one of the deciding votes to end Republicans' efforts to repeal Obamacare and tried to tank Trump’s most recent pick to lead the CIA.

And yet, of the wealth of words we have from McCain to illustrate how much he disagreed with the direction Trump was taking the Republican Party and the nation, perhaps no paragraph stands out as much as this one below. It’s from McCain’s last memoir, “The Restless Wave,” where the senator, battling brain cancer, reflects on the life he led and the world he would soon be leaving. To him, those two moments had clashed with the rise of Trump into an uncertain future:

The moral values and integrity of our nation, and the long, difficult, fraught history of our efforts to uphold them at home and abroad, are the test of every American generation. Will we act in this world with respect for our founding conviction that all people have equal dignity in the eyes of God and should be accorded the same respect by the laws and governments of men? That is the most important question history ever asks of us.

“The Restless Wave,” by John McCain

McCain felt that Trump had brought the nation to a generational crossroads about how it interacts with the world.

Would Americans embrace Trump’s more inward-looking foreign policy, in the form of tariffs and closing borders and deriding global alliances and shying away from getting involved in other countries' conflicts? Or would the more hawkish foreign policy that defined the Iraq and Vietnam wars come back into favor? It is a decision that McCain believed would define how history remembers this time and its leaders.

Whether the Republican Party sans McCain listens to his warnings about Trumpism is another question entirely. It didn’t seem to while the senator was alive. When the Republican-controlled Senate takes actions against Trump, it’s mostly in the form of symbolic, nonbinding resolutions. Only once since Trump began his presidency has Congress passed legislation to confront the president (by forcing him to sign sanctions against Russia). Overall, the trend is that Trump has forced Republicans in Congress to accept his policies on trade and immigration and farming subsidies that the party has traditionally been diametrically opposed to.

At this point, it’s an open question what Congress’s last straw with Trump could be. McCain left no doubt that he had had it with this president, and that nothing more than the integrity of America’s reputation is at stake right now.