Two members of a new generation have taken center stage in the campaign for the presidency. The cohort first called the Baby Bust, then “Generation X,” includes Republican Senators Marco Rubio and Ted Cruz.

Cruz or Rubio are vying for the nomination with Donald Trump—an entitled representative of the obscene over-consumption of the Baby Boom generation.  Then comes Baby Boom’s political poster girl, Hillary Clinton, 68.

Welcome to 2016, the battle of the generations.

The emergence of Cruz, 45, and Rubio, 44, and the support each garners from their Gen-X peers, signals the start of an era in which people of my generation, born between 1965 and 1985, will run most American institutions.

Gen-X is more ethnically diverse than any of its predecessors, partly a product of a 1970s immigration influx that filled the baby bust’s labor market gap. Cruz and Rubio, both sons of Cuban political émigrés, fit comfortably in their eclectic peer group.  

Other high-achieving Gen-X politicos like Governor Nikki Haley, 44, of South Carolina and former Louisiana Governor Bobby Jindal, 44, are also children of immigrants. Like Rubio and Cruz, none of the four embrace the hyphen-hyping ethnic politics of older politicians.

That overt rejection of niche identity is perhaps a learned Gen-X trait, shaped by a lifetime of melting-pot television, from Sesame Street to The Cosby Show to early MTV, that steered away from ethnic grievance. These are the kids who grew up on iconic 1980s songs like “We Are the World” and events like “Hands Across America,” not the battle lines of the bra-burning and the civil-rights 1960s. They suffered through lectures by hippie-boomer professors preaching cultural-sensitivity training more suited to the professors’ youth than to theirs. They chortle at today’s 20-somethings’ quest for “safe spaces” and fear of “hate speech.” Both deviations square with generational cycle theory, a view that key mores of a cohort emerge as reactions to the prior group.

It’s notable that neither Rubio nor Cruz comes from political or economic royalty. They bootstrapped their own way up. Gen-X did not inherit the military structure of the Greatest Generation, the class structure of the Silent Generation, nor the automatic economic growth given to the Baby Boomers. Instead, they inherited the latchkey kid autonomy that came from a skyrocketing divorce rate, and the adult career uncertainty ushered in by post-industrial economic transition.

Academic researchers formulaically note Generation X’s self-starting nature—and Cruz and Rubio make fitting political prototypes of that trait, having won just two statewide races between them when they launched White House bids. That upstart quality alone would make either the unlikeliest Republican nominee since 1964.

The GOP has been America’s Tory Party, buttoned-down and laddered-up, respecting brand names and blue bloods. Its nomination has more often been inherited than earned.

Republicans’ last three nominees were among America’s most famous progeny. Mitt Romney’s father was himself a governor, car-company CEO, and presidential candidate. John McCain was the son of a wartime Navy admiral, and George W. Bush the son of a president and grandson of a senator.

Further back, the nominees were just as prominent, men who had waited in line. Bob Dole was not nobly born, but had spent two decades at the top of the insider pyramid, married to a cabinet secretary to boot. Ronald Reagan and Dick Nixon had toiled in the presidential fields for years and waited on their spots. Gerald Ford was the sitting president.

Beyond their quick rise, their ethnicity, and their mutual devotion to meritocracy and individualism, Rubio and Cruz diverge. Cruz’s conservatism is gloomy, warning about what the United States might lose as a nation and harkening back to a gauzy past. Rubio’s is sunny and optimistic, focused more on what more the country might yet do.

That tonal difference might be seen, years from now, as a seminal battle for the GOP’s generational direction. In the early stages of the 2016 race, Cruz’s anger mirrors an electorate furious at the liberal over-reach of Boomer Barack Obama, and the profligate spending of “compassionate conservative” Boomer George W. Bush.

Cruz’s connection with the oldest Republicans more likely to vote is why, before his recent slips in South Carolina and Nevada, handicappers gave Cruz the slightest of advantages.

But Rubio’s message has found an audience that might say more about where the Party is going, if not where it is now. It’s among the other emerging Gen-X leaders of the GOP.

From Haley to Jindal to Senator Cory Gardner, 41, to the GOP’s two most prominent African Americans, Representative Mia Love, 40, and Senator Tim Scott, 50, it’s Rubio who’s sweeping the Gen-X endorsements.

He has in his corner Representative Jason Chaffetz, 48, Congress’s youngest committee chair, and more of the rising stars who gave Republicans control of Congress in 2010, people like Representative Kristi Noem, 44, and Representative Jaime Herrera-Beutler, 37.

The Gen-Xers’ lot in life has always been to be out-numbered and out-shined. The Boomers had more swagger—hence the derisive, generic name they assigned to the cohort that included their own children. The next generation, the Millenials, were assigned more historical significance.

Either Rubio or Cruz would run in November as an underdog, but it will be more than a partisan battle—it’s a generational reckoning.

Hillary Clinton is inseparable from the Vietnam-era culture that shaped her. Her campaign rests on a musty 1960s notion that historical discrimination against her gender entitles her to this victory. She argues that collective action only happens when compelled by government force. She sees a nation beset by scarcity, and believes redistributionist schemes are needed to correct it.

Clinton is selling structural, tribal, identity politics wedded to top-down institutional solutions.

None of that campaign matches with Generation X’s bent toward bottom-up voluntary philanthropy, its digital-age belief in the empowerment of the individual, or the self-reliance that has made its members avoid joining any kind of institutions at all—civic, religious, or political.

When most Americans met Hillary Clinton in 1992, she was helping the first All-Boomer ticket, including her husband, sideline World War II’s Greatest Generation from the White House for good. It would be all too fitting if her last campaign saw the torch pass once again.