On Monday in New Hampshire, Marco Rubio virtually accused President Obama of treason. “It’s now abundantly clear,” the Florida senator declared, that “Barack Obama has deliberately weakened America.” The president, Rubio continued, wants to “humble” the United States because he believes “our power has done more harm than good.” Essentially, Obama hates America and is working to bring it down.

Why is Rubio accusing Obama of purposely sabotaging America’s well-being? It probably has less to do with Rubio’s analysis of international politics than with his analysis of Republican primary politics. Basically, he’s been Trumped.

Obama entered the White House believing that America was overstretched. He believed George W. Bush’s decisions to invade Iraq and Afghanistan, in wars paid for on the national credit card, had hollowed the American military, distracted the country from challenges at home, cost trillions, and damaged America’s reputation overseas. So, like Dwight Eisenhower during Korea and Richard Nixon during the waning years of Vietnam, Obama sought to end costly land wars and bring America’s international commitments into better alignment with its resources.

One can argue that Obama’s analysis was wrong, or that he executed it poorly, but it was designed not to weaken American power but to preserve and regenerate it. If Rubio doesn’t understand that, then he doesn’t understand that a nation’s power is not measured by the size of its military footprint. The Soviet Union did not grow more powerful when it sent tens of thousands of troops into Afghanistan, just as the United States did not grow more powerful when it sent hundreds of thousands to Vietnam. Sending troops and weapons overseas can sap a nation’s power as easily as they can boost it.

Rubio didn’t always speak this way. He began his campaign with a message of optimism, inclusion, and goodwill. He announced his candidacy at the Freedom Tower, Miami’s Ellis Island, where he quoted his father in Spanish in front of a heavily Latino crowd. A few days later, in a Spanish-language interview, he said he would attend a gay wedding. Asked about Black Lives Matter in August, he mentioned an African American friend who had been stopped by police “eight or nine times” in the past 18 months and then declared that racism in the criminal-justice system was “a serious problem in this country.”

Rubio’s rhetoric has changed since then. He still mentions his immigrant background. “Immigration is not an issue that I read about in the newspaper or watch a documentary on PBS or CNN,” he said at a Republican debate last month. “It’s an issue I've lived around my whole life. My family are immigrants. My wife's family are immigrants. All of my neighbors are immigrants.” But he now says that undocumented immigrants would be ineligible for citizenship while he was president. He rarely speaks Spanish at campaign events, and unlike Jeb Bush, Hillary Clinton, and Ted Cruz, has produced no Spanish-language ads.

Part of Rubio’s initial pitch was his comfort with the more diverse, more tolerant America of 2015. Now, he advertises his discomfort with it. “This election,” he declared in an ad last month, “is... about all of us who feel out of place in our own country... millions with traditional values branded bigots and haters.”

The reaction to the ad was telling. “Marco goes full-on nativist,” declared MSNBC’s Joe Scarborough, who rightly accused Rubio of pandering to the Trump supporters who resent America’s darkening skin tone. But instead of ignoring Scarborough’s attack, the Rubio campaign amplified it, declaring that, “Democrats, the media and the political establishment” are “absolutely terrified” of Rubio’s new message.

It would be closer to the truth to say that Rubio is terrified by the fact that the “political establishment” likes him so much. Over the course of 2015, he eclipsed Jeb Bush and Chris Christie to become the darling of GOP donors in part because those donors saw him as capable of wooing the young and minority voters a Republican must win. In previous cycles, this kind of anointment would have been an unmitigated benefit. But this year, when so many Republican primary voters actively loathe their party’s elite, Rubio’s reputation as the establishment’s man is very much a mixed blessing. Here’s how Ann Coulter, who sometimes warms up Trump’s crowds for him, describes Rubio in her book, Adios America:

"The practiced liars in the Republican Party know damn well Americans do not want more immigration, but the leadership won’t give it up. To please well-heeled donors, elected Republicans compulsively push for amnesty... And the media cover for them: Don’t worry, we won’t write about what you’re doing with immigration! And if we do, it will only be to talk about your moral courage, Marco."

Rubio could have run as the anti-Coulter and the anti-Trump. Instead of trying to appeal to those Republicans who think Obama hates America and fear the demographic changes he embodies, Rubio could have run as John McCain did in 2000, when the Arizona senator called Jerry Falwell and Pat Robertson “agents of intolerance.” Although such a strategy might have hurt Rubio in conservative Iowa, it could have helped him in New Hampshire, where Republicans are more moderate culturally and where Independents can vote. Instead, Rubio is trying to appease the conservatives who distrust his immigration record and his establishment ties by sounding like Trump-lite.

Will it come back to haunt him if he becomes the nominee? Who knows? Mitt Romney’s shift right to the right on immigration during the primaries did, but Romney wasn’t running to be the first Latino president. People close to the Rubio campaign marvel at the way Latino hotel workers line up to shake his hand every time he walks into a banquet hall.

But whether or not Rubio’s evolution hurts him politically, it says something depressing about today’s GOP. It shows that, for the time being at least, it’s Trump’s party. Even a politician as gifted as Marco Rubio must play by The Donald’s rules.

This article was first published in The Atlantic.