The death of Dianne Feinstein isn’t just the end of a pathbreaking life. Or a generational shift in power in the U.S. Senate.

It’s the severing of a crucial link holding California and the United States together.

In her half-century in public office, Feinstein played many roles and came to mean many different things to Californians, especially those in her hometown of San Francisco. But for the Golden State as a whole, her most important job was an unofficial one: She was California’s ambassador to the American government.

This job was challenging, and it became more so during the 30 years she spent in Washington, D.C. In that period, California, always an exception, grew rapidly apart from the rest of the country.

Over Feinstein’s tenure in the Senate, the Golden State became a more progressive and democratic place, even as much of America turned inward, into conservative populism and right-wing nationalism. As everyday Californians demanded more freedom, a conservative U.S. Supreme Court curbed rights. And as our state government grew more aggressive and embraced experimentation, the federal government became stagnant and dysfunctional.

In this era of accelerating polarization and side-taking, Feinstein was an outlier. She played for both sides.

She believed deeply in California, and its increasingly liberal values on LGBTQ issues, on women’s rights, on gun control, on protecting the environment, on advancing democracy. But she also believed deeply in the American system of government, in the anti-democratic U.S. institutions, including a Senate that all too often frustrated attempts to realize those values.

She didn’t just reconcile the contradictions of representing her state and her country. She built her career on doing just that. How? One answer, as her closest friends would tell you, was sheer brains. She embodied the famous observation of F. Scott Fitzgerald, the great chronicler of the phoniness of American ambition: “The test of a first-rate intelligence is the ability to hold two opposing ideas in mind at the same time and still retain the ability to function.”

The other answer was her legendary stubbornness, which was her real superpower. You’d have to be stubborn to commute across a large country for 30 years, to serve a state in a hostile national capital. You’d have to be stubborn to serve as a human bridge between two shores moving away from each other.

It helped that Feinstein was a wealthy woman with a talent for holding a party. California’s unofficial embassy in Washington was her home—in her early Senate years, a five-story townhouse in Kalorama, and later, a very ambassadorial $10 million estate.

As a diplomat, she knew her job was to talk to opponents and enemies, and so many of the guests were Republicans. She took the bullet for Californians and played nice with Chuck Grassley and Mitch McConnell and all manner of right-wing pols whose existence turned the stomachs of her voters back in the Bay Area.

It was no accident that the Republican to whom she grew closest was Sen. Susan Collins of Maine. Collins’ vote could swing the Senate, and decide whether Feinstein could get California the budget items and policy carveouts it needed. Is it any wonder that Feinstein organized an engagement party for the Maine senator, or gifted her a painting that hangs prominently in Collins’ office?

Feinstein practiced diplomacy with American enemies and rivals; she had the closest ties with important Chinese figures of anyone in Washington, keeping open lines of communication in the world’s most important relationship. Feinstein also employed her diplomatic skills to keep the fractious Democratic coalition—which included California’s all-too-few allies—together. Barack Obama and Hillary Clinton met at her home to reconcile after the 2008 primaries.

But it became harder to be a diplomat as Washington grew angrier and more conservative. The Bush years saw the undoing of what should have been her legacy. The assault weapons ban she had pushed to passage in 1994 expired in 2004, despite all her efforts to renew it. And the cruel Trump years made her longstanding bipartisan efforts to reform immigration and prevent the government from using torture seem daft. The U.S. government, which she loyally served, had become a monster, capable of building concentration camps for migrant children.

A bitter irony, left unmentioned in the obituaries, is that her major enduring legislative legacy was the empty desert she preserved, via the California Desert Protection Act. Politically, her devotion to diplomacy, and her personal embrace of Republicans like Lindsey Graham, came to seem at best out-of-touch, and at worst, dangerous. Her friend Sen. Collins approved the Trump-appointed Supreme Court justices that would revoke women’s reproductive rights and block reasonable gun controls.

In 2018, the California Democratic Party, tired of Feinstein’s diplomacy and bipartisan conciliation, endorsed a combative opponent, Kevin de León, against her. “California Democrats are hungry for new leadership that will fight for California values from the front lines, not equivocate on the sidelines,” De León declared.

Feinstein won the election anyway, but her base of support collapsed. As she showed more signs of age, liberal groups and former allies called for her resignation.

At her death, she was the most unpopular Democratic politician in California.

Ultimately, Feinstein’s ambassadorship failed because California and the American government had simply moved too far apart. As a result, we live in a new Cold War, between our state and our nation, which Feinstein tried to prevent.

We also live in an era of daily mass killings with the assault weapons Dianne Feinstein couldn’t permanently ban. We live in a surveillance state that Feinstein sought to limit. We deport, without due process, unauthorized immigrants Dianne Feinstein wanted to integrate into American life. We now barrel toward war in East Asia while barely talking to a China that Dianne Feinstein had on speed dial.

It’s telling that Feinstein’s replacement, chosen by our culture-warmongering governor, is a hardnosed labor and political operative with experience in partisan battles. And it’s unsurprising that the leading candidates running to fill her seat are three of the most polarizing members of the House of Representatives.

These would-be Feinstein successors have recently issued statements praising her, but they won’t try to fill her shoes. No one wants to play Feinstein’s role anymore.

Rest in peace, dear Dianne, our last ambassador.