Alaska Sen. Lisa Murkowski became the third Republican U.S. senator to support same-sex marriage Wednesday, just days before the Supreme Court is set to decide on its constitutionality. But what’s really significant about Murkowski’s decision is the argument she made in an op-ed, rooted squarely in family values.

In explaining her evolution on the issue, Murkowski told the story of an Alaskan military couple who visited her on Capitol Hill for lunch with their four foster children. The kicker was that the couple was two women.

As Murkowsi explained: “After their years of sleepless nights, after-school pickups, and birthday cakes, if one of them gets sick or injured and needs critical care, the other would not be allowed to visit them in the emergency room—and the children could possibly be taken away from the healthy partner. They do not get considered for household health-care benefit coverage like spouses nationwide. This first-class Alaskan family still lives a second-class existence.”

Amen. But here’s why her argument really mattered—it is a conservative-values-based case for what had been the least traditional family arrangement imaginable in the past. It reflects the sea change in society that is still under way. And it is an argument that might not just eventually win over more conservative converts; it might win over a strategically placed Republican justice.

In Hollingsworth v. Perry, the case contesting the constitutionality of California’s same-sex marriage ban, Justice Anthony Kennedy said this: “There are some 40,000 children in California ... that live with same-sex parents, and they want their parents to have full recognition and full status. The voice of those children is important in this case, don't you think?”

Murkowski’s passionate statement of principle is consistent with Kennedy’s concerns. But she also framed her argument in political and even partisan terms: “I am a life-long Republican because I believe in promoting freedom and limiting the reach of government. When government does act, I believe it should encourage family values. I support the right of all Americans to marry the person they love and choose because I believe doing so promotes both values: it keeps politicians out of the most private and personal aspects of peoples’ lives—while also encouraging more families to form and more adults to make a lifetime commitment to one another.”

This combines the core individual liberty argument that conservatives hold dear with the family-values rationale that motivates social conservatives. It has the makings of rebuilding the big tent.

Murkowski is an independent-minded Republican. In fact, she was elected on a write-in ballot as an independent after losing the GOP primary in 2010 to a Tea Party–backed candidate. But she nonetheless represents the most red state to date to have a senator back marriage equality—the other two are Ohio’s Rob Portman (who was compelled to change his position by a gay son) and Illinois’s Mark Kirk.

It is far too early to say that Murkowski represents anything like a tipping point. While a majority of the American people now support same-sex marriage, elected Republicans see only the political liability from their base. The National Organization for Marriage lost little time in threatening her politically, saying, “Murkowski has betrayed marriage and the overwhelming majority of Alaskans who have voted to define marriage as the unique union of one man and one woman. She has sealed her political fate."

Murkowski preemptively addressed that attack in her op-ed by writing, “If there is one belief that unifies most Alaskans—our true north—it is less government and more freedom. We don’t want the government in our pockets or our bedrooms; we certainly don’t need it in our families.”

It is refreshing to hear the substance of libertarian beliefs coincide with its stylistic invocation. This is the way to address some of the core contradictions at the heart of the conservative coalition and connect to a new generation. The three Republican senators who now support the freedom to marry now balance out the three red-state Democratic senators—Mark Pryor, Mary Landrieu, and Joe Manchin—who currently don’t support marriage equality.

While the demographic data are in, we are still a long way from this being a settled issue in Republican politics. It is hard to imagine that a successful 2016 GOP nominee will have the political freedom to support the freedom to marry. And if the Supreme Court does not overturn the Defense of Marriage Act, senators like Kirsten Gillibrand have already promised to try and overturn the law with a legislative vote, which at least currently seems short of the 60-vote threshold. But at a time when it’s easy to point to examples of conservative populist reaction pandering to the GOP base, Lisa Murkowski’s eloquent declaration of independence is something to celebrate.