In his July 2025 speech accepting the Claremont Institute’s Statesmanship Award, the vice president argued that defining America solely by its founding creed, the Declaration of Independence’s proposition that all men are created equal, is both “overinclusive and underinclusive.” Overinclusive because it could theoretically embrace millions abroad who agree with America’s principles. Underinclusive because it risks overlooking the historical communities, traditions, and inherited loyalties that helped create the nation in the first place.

This is not an academic dispute. It may become the central ideological contest inside Republican politics after President Donald Trump leaves the stage.

Trump has been the one figure capable of holding both camps in coalition simultaneously. His departure will remove the only leader who has successfully bridged the divide. The 2028 primary may be the first real test of whether that coalition survives him or fractures along a fault line he largely papered over.

Both Rubio and Vance are plausible heirs to the coalition Trump assembled. Both serve in the same administration. Both are popular with Republican voters. Both could seek the presidency in 2028. The problem is that only one can define the party’s future.

At its core, the disagreement is about what makes someone fully American.

Vance raises a legitimate concern. A creed alone does not make a nation. Shared history matters. Civic memory matters. A common language matters. Assimilation matters. A country cannot survive if citizenship becomes nothing more than an agreement with a set of abstract propositions.

But Vance’s supporters would argue the concern runs even deeper. They worry that America’s founding principles cannot survive without a culture capable of transmitting them. In their view, the real question is not whether immigrants can become Americans. It is whether the institutions that once assimilated newcomers still function. A nation that loses confidence in its own traditions eventually loses the ability to pass on the very ideals it claims to cherish.

The question is what follows from that observation.

For most of American history, the answer was that newcomers could enter the culture, adopt it, contribute to it, and eventually become part of it. America was never merely an idea, but neither was it a bloodline. It was a civilization open to those willing to join it.

That distinction matters because America has repeatedly expanded not by abandoning its culture but by inviting others into it. The Irish, Italians, Jews, Cubans, Vietnamese, and countless others became Americans not because they shared ancestry with the founders but because they embraced the country’s institutions, traditions, and ideals.

President Abraham Lincoln understood this better than anyone. America, he argued, was connected by what he called the “electric cord” of the Declaration of Independence. A person could arrive from anywhere, speak any language, and carry any surname, yet still become fully American through commitment to the nation’s principles and institutions.

Rubio’s life story is a modern version of that argument.

Every time he tells the story of his parents, he is making a political point, whether he intends to or not. Their journey from Cuba to the American middle class embodies the belief that conviction, effort, assimilation, and opportunity matter more than ancestry. What made them American was not where they came from — it was what they chose to join.

That belief has shaped Republican politics for decades. It explains the party’s strength among Cuban Americans and its growing appeal among many Hispanic voters. It provides a language for opposing authoritarian regimes abroad while celebrating legal immigration at home. Most importantly, it reinforces the idea that American identity can be inherited by choice as well as by birth.

Trump largely succeeded because he refused to choose between these traditions. He spoke the language of borders, national cohesion, cultural confidence, and historical continuity that appealed to Vance’s supporters. At the same time, he celebrated entrepreneurs, legal immigrants, and success stories like Rubio’s as proof that the American dream remained alive. His coalition united people who shared frustrations even when they did not share the same theory of nationhood.

No one else has demonstrated that ability.

That may be the hardest challenge facing the Republican Party after Trump. A coalition broad enough to contain both Rubio and Vance may prove harder to sustain once voters are forced to choose between them.

The 2028 primary will not be fought as a seminar on political philosophy. It will revolve around immigration, citizenship, education, national identity, economic issues, and the meaning of assimilation. Yet beneath those arguments lies a deeper question: Is America primarily a historic people joined by culture and continuity, or a nation whose culture can be entered by newcomers willing to embrace it?

The answer matters because the Republican Party’s future may depend on it.

Vance offers a richer emphasis on history, continuity, and the institutions that sustain national identity. Rubio offers a vision rooted in assimilation, opportunity, and the American creed. Both speak to genuine elements of the American experience. The question is which one will become the dominant language of post-Trump conservatism.

The more profound issue is not which man wins in 2028 — it is what Republicans will have decided America is by the time one of them does.

For more than two centuries, the American model combined a shared culture with an open door to those willing to adopt it. It became the most successful multiethnic democracy in history not by ignoring culture but by treating culture as something newcomers could enter and inherit.

The coming debate inside the Republican Party is whether that understanding remains sufficient.

WHY I CAME TO AMERICA, AND WHY I STAYED

Rubio’s biography represents an America that believes people can become part of the nation through commitment, assimilation, and shared civic ideals. Vance’s political project asks whether those ideals can survive without a deeper attachment to history, place, and inherited culture.

The debate between them is not merely about who leads the Republican Party after Trump. It is about which understanding of America will guide it.