Senator John McCain (R-AZ) doesn't want President Donald Trump to attend his funeral, reports say. The Grand Canyon State's senior senator has been making his final arrangements due to his ongoing battle with brain cancer.

According to the New York Times, McCain wants former President Barack Obama to deliver a eulogy, and has urged former Vice President Joe Biden to "remain in politics." McCain, 81, also reportedly wants current Vice President Mike Pence to be in attendance for his eventual, and perhaps soon approaching, memorial service.

When it comes to Trump, however, the senator is singing an entirely different tune. McCain and Trump have clashed over immigration and trade policies, as well as the president's apparent attraction to autocratic world leaders. Trump has attacked McCain and his military service, including the period McCain was held as a prisoner of war during the Vietnam War. "I like people who weren't captured, okay?" Trump said of McCain during the 2016 presidential campaign.

McCain made it clear that he doesn't want Trump anywhere near his funeral.

"He seems uninterested in the moral character of world leaders and their regimes," he writes of the president in his upcoming book, The Restless Wave. "The appearance of toughness or a reality show facsimile of toughness seems to matter more than any of our values. Flattery secures his friendship, criticism his enmity."

The Arizona Republican has also expressed his regret over picking Sarah Palin, the former Republican governor of Alaska, as his running mate in the 2008 presidential race. Palin was one of the earliest and most vocal members of the Tea Party movement, which espoused extreme right-wing views and absolutely disdain for Obama. In his book, McCain recalls that he felt pressured to put Palin on the ticket despite his instincts, which were leaning toward nominating Senator Joe Lieberman (I-CT).

"It was sound advice that I could reason for myself," he writes. "But my gut told me to ignore it and I wish I had."

McCain was elected to the Senate in 1992 and has often been described as a "maverick" for his willingness to reach across the aisle and promote compassionate conservatism.