For a long time now, I’ve been talking about 21st century conservatism—about why we should modernize, but not moderate—and about how conservatism is the best philosophy for anyone who wants to achieve the American Dream. I even wrote a book about it.

Well, South Carolina Governor Nikki Haley’s endorsement of [crscore]Marco Rubio[/crscore] yesterday taps into this theme. Here you have the daughter of immigrants endorsing the son of immigrants for the Republican nomination to run for the most important job in the world. Aside from this remarkable aspect, politically speaking, the endorsement also gave Rubio’s campaign a shot in the arm—and could possibly impact the future direction of the GOP. It’s unclear whether the momentum will be enough for South Carolina to make Rubio the “comeback kid,” but he does seem to have regained his momentum after that disastrous New Hampshire primary debate.

Again, though, it’s important to appreciate the magnitude of what happened yesterday: A 43-year old female, Indian-American Republican governor of South Carolina—and an African-American Republican U.S. Senator (Tim Scott)—are now both endorsing a Hispanic-American Republican U.S. Senator. All three are conservatives. And this is happening in South Carolina.

This could be the future of the Republican Party. But it stands in stark contrast to a GOP that is remade in the image of Donald Trump.

Speaking of Trump, yesterday I warned that it’s time for mainstream conservatives and “establishment” Republicans to hit the “panic button.” Haley must have been thinking the same thing, which might explain why she decided to make an endorsement.

Her desire to stop Trump-ism shouldn’t surprise us. During Haley’s Republican rebuttal to President Obama’s State of the Union Address last month, she warned that “it can be tempting to follow the siren call of the angriest voices,” but we “must resist that temptation.” The line was a veiled shot at The Donald. And everyone knew it.

Haley skillfully and eloquently rebutted President Obama’s liberal agenda, too. But she provided more than a rhetorical response. Haley personifies a brand of serious conservatism utterly at odds with the demagogic bluster that marks the Republican primary campaign. Some of this is biographical. “I am the proud daughter of Indian immigrants who reminded my brothers, my sister and me every day how blessed we were to live in this country,” she said. But her appeal transcends identity politics.

Haley’s conservatism—and what she represents—is no less than an alternative vision of the GOP, and one that the party desperately needs. “If you want to hear an inclusive leader who’s visionary, who’s got a path for the future, who’s brought people together, who’s unified: it’s Nikki Haley,” said Speaker of the House [crscore]Paul Ryan[/crscore] in an interview on CNN the Monday before her SOTU response.

In her response, Haley both rejected Obama’s policymaking, but also the angry and divisive rhetoric that permeates the Republican primary campaign trail. “It was the best written and best delivered answer to the State of the Union Address I’ve ever heard,” said conservative columnist Charles Krauthammer on Fox News.

Not surprisingly, though, representatives of the GOPs populist “Know Nothing” caucus were not pleased. “Trump should deport Nikki Haley,” conservative provocateur Ann Coulter tweeted during Haley’s rebuttal had even concluded. Others, like conservative talk radio host Laura Ingraham, piled on.

Haley wasn’t flustered. Over the years, she has proven her mettle.

Consider her handling of the Confederate flag last year. In the wake of the June shooting at Mother Emanuel, a storied African American Methodist Episcopal church with one of the oldest black congregations, in Charleston, South Carolina, that killed nine worshipers, pictures emerged of the shooter flaunting a Confederate battle flag, the same flag that still stood on the state capitol grounds. Calls grew for the flag to come down from the statehouse—in a state that was first to secede from the union and where pro-flag sentiment has proven durable.

Haley responded with real, mature conviction. “This flag, while an integral part of our past, does not represent the future of our great state,” she declared. She urged the South Carolina legislature to remove the flag and on July 10 it came down for good. Haley’s leadership on this issue drew wide acclaim, and rightfully so.

The episode was an important example of how pernicious cultural baggage that has nothing to do with conservatism (it was an all-white, Democrat-controlled legislature that raised the flag in 1962, after all) should be handled. If conservatives are going thrive in the New South, they will have to embrace the more inclusive message that Haley is helping provide.

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Amid the apocalyptic nationalism that has become common on talk radio and the presidential race, Speaker Ryan, who tapped Haley to give the State of the Union response (and invited a list of anti-poverty advocates to be his guests for the State of the Union address), is trying to promote a more optimistic, diverse, and thoughtful brand of conservatism. While Donald Trump and his imitators may prefer to stress the “outsider versus establishment” paradigm, the reality is that liberal Rockefeller Republicans are extinct. The real struggle taking place right now is between governing conservatives like Haley and Ryan—and their less philosophically conservative adversaries on the populist Right.

This conflict is as much about style, culture, and temperament as it is about ideology or policy positions. Haley is a legitimate conservative. “She weathered the rough and tumble world of South Carolina politics to become a real champion of honest government and small government,” conservative Erick Erickson told me in an email just before her SOTU response. “The greatest thing about Governor Haley is what you see is what you get.  She’s a mom, a wife, a daughter, a real leader, and has a genuine appreciation of the American dream.”

So will the GOP continue to be a party that welcomes future Nikki Haleys? On Saturday, South Carolina voters will get to weigh in on that. This is a time of choosing. There is a conflict of visions. Republicans can double down on working class rural white voters who are (in many cases justifiably) angry and frustrated, or they can embrace a more optimistic, dynamic brand of conservatism, a more Haley conservatism, that is far more likely to attract minorities, urban voters, and millennials.

Haley represents the serious, governing wing of the conservative movement. Her critics do not.

The good news is that she is merely one of many up-and-coming conservative leaders on the Republican “bench” right now. The bad news is that they might not feel much at home in the GOP—if Trump redefines it. They represent the real potential of the Republican Party—not a billionaire casino magnate who gave money to Hillary Clinton.

Whoever wins the Republican Primary election, he would be smart to look for a running mate like Nikki Haley.