A few hours before Hillary Clinton announced Tim Kaine would be her running mate, I had an interesting conversation with Stuart Stevens, Mitt Romney’s 2012 campaign manager. The topic was Donald Trump. These days, the topic is always Donald Trump. But Stevens’s analysis of the election offered a useful window into why Clinton chose Kaine.

"Trump is 4 points behind Romney with white men," he said. "He’s 11 points behind with white women. The electorate is white men, white women, nonwhite men, and nonwhite women. To win, you have to do better than Romney with one of those groups and Clinton’s got to do worse. Which is it? I don’t see it."

This kind of demographic analysis is crude, to be sure. But it helps explain the political dimension of the Kaine pick (there’s another, more important dimension that I’ll get to in a minute). He’s a white man who wins elections in Virginia, speaks fluent Spanish, and used to sue landlords for turning away African-American renters.

Let’s begin with the Virginia thing. The New York Times has a handy widget that lets you explore how each candidate’s path to the nomination changes as the candidate wins and loses different swing states. If Clinton wins Virginia, she’s left with 494 viable paths to the election. Trump is left with 16. Virginia, in other words, is a big deal, and if Kaine can help her win it, Trump’s path to the White House narrows considerably.

Trump’s only hope of winning the general election is to mobilize a white backlash vote that didn’t manage to manifest even against the first African-American president. It’s not a terribly likely strategy, but perhaps Trump’s more explicit appeal to white resentment gives him a shot.

What Clinton has in Kaine is a vice presidential candidate who doesn’t help Trump’s effort to mobilize a white male backlash and may even help blunt it, but who is also able to appeal to the Democrats’ multicultural coalition: Kaine was the first member of the Senate to deliver a floor speech in Spanish, and while mayor of Richmond, Virginia, he made headlines for officially apologizing for the city’s role in slavery.

In general, I don’t think the evidence suggests that vice presidential candidates routinely swing elections; Kaine’s impact on the race is likely to be marginal. But it’s easy to see why he fit Clinton’s strategy: He makes Trump’s job that much harder with white men, and makes Clinton’s job that much easier with African Americans, Hispanics, and Virginians.

Of course, the question behind any vice presidential pick isn’t whether he makes the president’s job easier but whether he can do the president’s job in the event of a catastrophe.

I don’t pretend to know Kaine well enough to say whether he should serve as president. What I have noticed covering Kaine, though, is that he really seems to impress his fellow politicians.

In 2006, mere days after he was sworn in as governor of Virginia, Democrats tapped him to give their State of the Union response. In 2008, he was one of three names on Barack Obama’s shortlist for the vice presidency. In 2009, Obama named Kaine to chair the Democratic National Committee.

All this might make sense if Kaine was a thrilling speaker, or the first elected official to hail from a particularly marginalized group, or had some kind of backstory that brought tears to your eyes, or was the only elected Democrat to hail from a swing state. But none of that’s true. Reporters tend to describe Kaine as "boring" and "safe." He was picked over colleagues from Ohio and Florida. Whatever is so impressing Kaine’s colleagues isn’t a public-facing skill.

Clinton is perhaps Kaine’s most surprising admirer. Kaine was one of the first statewide elected officials outside Illinois to endorse Obama in the 2008 race. The endorsement was an early blow to Clinton’s hopes — the backing of a popular Southern governor showed that Obama’s appeal extended beyond the liberal base.

But Kaine managed to go from opposing Hillary Clinton when she needed him most to persuading her — and her husband — that he’s the person who should be president in the event of her death.

There is something about Kaine that his colleagues don’t find boring. There is something that makes him stand out, inspire confidence, win their trust, get tapped for key jobs. And that’s probably the more important rationale behind Clinton’s pick. She needed someone who will help her win the election, but she also needed someone she trusted with the job. She came to trust Kaine. And she’s hoping the country will, too.

The headlines I saw in the hours after the pick — including at Vox — largely emphasized that Kaine was a "safe choice." Usually, that’s not how you want your VP described, but the Clinton campaign might well wear that label as a badge of honor this year. Given the race Donald Trump is running, "Clinton-Kaine: the safe choice" actually isn't a bad slogan.