(CNN) George W. Bush doesn't talk much about politics in public. Which makes the speech he gave Thursday in New York City -- a point-by-point rejection of Trumpism -- all the more important and noteworthy.

The 43rd president of the United States -- and the last Republican to hold the office before Donald Trump -- didn't mention the 45th president by name in his speech at the George W. Bush Institute. But Trump -- and his views -- were ever-present in the former President's address.

Bush condemned "nationalism distorted into nativism."

He derided "discourse degraded by casual cruelty."

He acknowledged that "our politics seems more vulnerable to conspiracy theories and outright fabrication."

And, most importantly, Bush said that "bigotry seems emboldened."

The two speeches, taken together, amount to a verbal lapel-shaking by Bush and McCain of the Republican Party they have led over the past two decades. "Wake up!" Bush and McCain are saying to their party. "What Trump represents is neither Republican nor conservative. It is Trump. Which is fine for Trump but far less fine for the medium-to-long-term health of the Grand Old Party."

There will be some who question Bush's motives. (Trump, via Twitter, may be one of them.) After all, Trump savaged "low-energy" Jeb Bush during the 2016 campaign. And the Bush family is literally one of the cornerstones of the Republican political establishment. Of course they don't like that someone like Trump is overthrowing them -- and their failed policies and political tactics!

But it's important to remember that the presidency is viewed by those who have held the office as a sort of sacred trust. Yes, George W. Bush saw the world differently than Barack Obama did -- and each man pursued divergent policies in office. What they shared, however, was a fundamental desire to remind Americans of our common humanity, to look to the future as a more optimistic, more tolerant and, yes, better place. They believed in the idea that America was forever moving toward a more perfect union and that their job was to help steer the country in that direction as quickly and safely as possible.

That belief, which can be traced in a relatively solid line from the first president to the 43rd, was broken with Trump's victory. Trump painted a picture of a grim and failing country, one in which the only true path forward was to start focusing more on ourselves and a whole lot less on the rest of the world.

"America First." "Make America Great Again." These were (and are) slogans built on the idea that the movement of the last several decades has not been a relentless march toward a better place but rather a step -- or a series of steps -- in the wrong direction.

Trump's policy priorities -- a travel ban, building a wall along the southern border, repeal and replacement of Obamacare, pulling out of the Paris climate accords -- all function as a different notes in that same chord. The American Dream is almost dead. Only Trump can revive it -- with a singular focus on looking out for number one again.

It's easy to paint Trumpism as solely a rejection of Obama's presidency. But to do so would be to ignore the degree to which Trump has sought to undo Bush's focus on on free trade agreements as a way to guard against global protectionism, his belief in the need for comprehensive immigration reform as consistent with the founding ideals of the country and his unwillingness to paint Islam with the broad brush of terrorism.

Bush's speech Thursday was a re-assertion of those views and, as such, a rejection of Trumpism.

"We become the heirs of Martin Luther King Jr. by recognizing one another not by the color of their skin but by the content of their character," Bush said toward the end of his speech. "This means people of every race, ethnicity and religion can be fully and equally American. It means that bigotry or white supremacy in any form is blasphemy against the American creed. It means the very identity of our nation depends on the passing of civic ideals to the next generation."

Those are powerful words. The question is whether Trump -- or the Republican Party he is remaking in his image -- are listening.