I’ll never forget Bill Clinton’s speech to the Democratic National Convention. The one four years ago, in Charlotte.

It’s the best speech I’ve ever seen in person. And hands down the best speech ever given by a former president. (Though I’m sure Teddy Roosevelt’s in 1912 were a sight to see, especially the one he gave minutes after being shot, and his speech about standing at Armageddon and battling for the lord is damn near appropriate this year.)

But Bill Clinton’s speech in 2012 was as good as it was long. And it made all the difference in the world.

The economy was still recovering. Voters were worried about progress under President Obama, and it took a president who presided over a great economy to sell Obama’s reelection.

The Big Dog is speaking again tonight and the stakes are somewhat different.

We know he’s for Hillary. And we know he’ll be passionate in her defense.

But his job tonight is not to promote his wife, it’s to defend himself.

More than against Hillary, and Barack Obama, Donald Trump is running against the politics of Bill Clinton: liberalism, centrism, free trade, meritocracy, government by experts, etc….

He’s not running against Obamacare. He’s running against NAFTA, NATO and the WTO; against the internationalism and the commitment to globalization that has always defined the Clintons.

Trump is not a threat to win Obama’s territory, in the cities and on college campuses he might even do worse. No, Trump is winning Clinton’s country: Arkansas, West Virginia, Kentucky and the undereducated white voters who used to have a home in Democratic politics.

Appalachia and the Deep South are gone now and Georgia is still a long shot for Democrats. The white working class is also gone, and winning them back will be a challenge for Democrats for a century to come.

But if Hillary Clinton is going to win this election, she’ll need the votes of middle-aged whites with college degrees who live in Ohio, Virginia and North Carolina. Folks who did well in the ’90s, but not since. Folks who owned small businesses or worked desk jobs, who saved for retirement, lost much of it in the recession, and now can barely afford a decent vacation.

The folks who supported the Clintons last time, but who are almost as skeptical of globalism now as the factory workers who lost their way of life.

If Hillary loses this election, her husband will have no more big speeches to give. If she wins, it will be in part because of what he says tonight, and whether, like he used to, he connects with the American people, and makes them believe deep down in their gut that things will be ok.

Clinton won’t be selling TPP from the stage. The audience at this DNC is so protectionist that it will be a huge undertaking to ever get it passed.

But it’s Bill’s job tonight to sell Americans on remaining involved in the world. We cannot retreat. We cannot look inward. We must, even in tough times, remember our responsibility to refugees, to our allies, and to each other.

And nobody does the politics of responsibility better than Bill Clinton. This is his last big speech in American politics, and I suggest you watch.