Sen. John McCain (R-Ariz.) and Sarah Palin in 2008. (AP Photo/Charlie Neibergall, File)

Much has been made, rightly so, of the fact that Sen. John McCain's family did not invite President Trump to his memorial service. McCain made no secret that he thought Trump was taking the country in the wrong direction, while Trump made no secret he resented McCain.

But perhaps a more telling non-invite is Sarah Palin. Politico, CNN and NBC News report that she won't be at Saturday's big service at the National Cathedral, the one where two former presidents who defeated McCain's bids for the White House, George W. Bush and Barack Obama, will deliver eulogies. Palin declined to comment "out of respect for Sen. John McCain and his family."

McCain ostensibly had plenty of time to orchestrate his memorial services as he battled brain cancer for a year before his death Saturday. That he would choose not to have his own vice presidential pick at his memorial service can be interpreted as a neon flashing signal to the world not just about his own personal regrets in life but how concerned he was about the rise of Trumpism — and perhaps his role in it.

The link from McCain to Trump goes something like this: The Republican senator from Arizona elevated Palin, then the GOP governor of Alaska, by picking her as his vice presidential nominee in 2008. Palin in turn helped stir up and elevate certain factions on the right -- notably the kind of people who called Barack Obama an "Arab." Eight years later, America elected a man to the White House who had questioned Obama's birth certificate and whose base of voters fit neatly into the same categories as those who supported Palin.

Nothing is ever that simple in politics, of course. Analysts have attributed the rise of hyperpartisanship and Trumpism to a confluence of events. There was the 2008 recession that aggravated polarization on both sides of the aisle. The weakening of campaign finance laws allowed outside groups to spend millions to steer politics in their preferred directions and made politicians dive for safety in the ideological corners of their party. Gerrymandering. Voters self-sorting into liberals in cities, conservatives in rural areas. Mistakes Democrats made in the 2016 presidential race.

We may never fully understand this unique political moment we're in until we're out of it.

But interpreted one way — the most obvious way — McCain seemed to have come to a conclusion about how Trump is president: He helped lead the way.

McCain's been sending us this signal for awhile now. Months before his death, he wrote in his last memoir that he regretted not picking Joseph Lieberman, an independent senator, for his vice president. Palin called that revelation a "gut punch."

These memorial services aren't just about looking back on McCain's life through a certain frame; McCain used his impending death to try to steer a country he thought was going in the wrong direction back to his vision of a hawkish America championing democracy abroad.

He was diagnosed with brain cancer, then voted against Republicans' efforts to repeal Obamacare. He gave speeches and wrote op-eds urging Americans to "fight" Trumpism. His very last statement, prepared to be read after his death, was an indictment of Trump.

And now his final memorial service, particularly his apparent decision not to invite Palin, can be read as an indictment of his role in it.