Drew Angerer / Michael A. McCoy / Getty

If, as John Nance Garner complained, the vice presidency is “not worth a bucket of warm piss,” then the quadrennial vice-presidential debate is usually worth even less.

Oh, sure, the undercard has produced its share of memorable sound bites, such as “You’re no Jack Kennedy,” “Malarkey,” “Who am I? Why am I here?” and “You whipped out that Mexican thing again.” But the debate, like the running mate, rarely makes any measurable difference in the election’s results.

This year’s debate, between Vice President Mike Pence and Senator Kamala Harris, might be worthwhile, though. For one thing, the first presidential debate was unwatchably bad, and the next two might be, too—should they even occur. Yet the two running mates seem more likely to have a substantive debate about the future of the country than those at the top of their ticket managed to conduct. What’s more, both Donald Trump, 74, and Joe Biden, 77, are old men, and Trump is sick with COVID-19. The actuarial chance that the next vice president will have to step up is at a historic high.

But either a Pence or a Harris presidency would represent a substantial shift from a Trump or a Biden presidency. Neither Trump nor Biden is an especially clear expression of his party. The president has abandoned many of the anti-entitlement, pro-trade pieties of the GOP; his challenger, meanwhile, sits decidedly toward the center of a Democratic Party moving steadily leftward. Pence and Harris much more cleanly represent those factions. The vice-presidential debate will be, in effect, a debate between the Republican past and the Democratic future.

Until Trump picked him as a running mate, Pence seemed an almost perfect expression of generic, post–Ronald Reagan Republicanism. He was a devout Christian, and sought to inject more religion into schools and government, but in most other respects he was a small-government crusader. He wanted trade free, taxes low, entitlements slashed, and (at least ostensibly) deficits minded. Pence had been a talk-radio host at one time, but since 2001, he’d been in the House and then the Indiana governor’s mansion. He was the Republican establishment.

Pence did not run for president in 2016—in fact, his career in Indiana seemed to be foundering—but his worldview was amply represented in the Republican primary, and resoundingly defeated by Trump. The eventual GOP nominee railed against free trade, promised to preserve entitlements, and was manifestly irreligious, even as he catered to evangelical voters’ views on abortion. (He is said to privately mock Pence’s faith.) That was just what Republican voters wanted, it turned out.

In the 2016 race, Pence served to shore up some of Trump’s weaknesses with reluctant Republicans. This cycle, his role is less clear. He has been an unswerving sycophant publicly, but Trump has now reshaped the Republican Party in his own image, leaving less room for Pence’s views, although the president has also abandoned his fidelity to preserving entitlements. What the GOP will look like after Trump is an open question. He is in some ways sui generis, but young Republicans, including Josh Hawley, Marco Rubio, Tom Cotton, and Ted Cruz, have begun searching for ways to formulate a Trumpism without Trump. A Pence 2024 run seems likely regardless of the result in November, but it is difficult to imagine his brand of conservatism triumphing.

Democrats, too, are striving to figure out what the future of their party looks like. Few of them seem to believe that Biden, an aging understudy of the last Democratic president, is the prototype. That includes Biden, who in March described himself as a “bridge” to younger leaders in the party. Some Democrats felt there was no need for a transition period, including Harris, who ran for president against Biden in 2020. But the young Democrats in the race were all resoundingly beaten, just like the traditional Republicans in the 2016 primary. The runner-up was Bernie Sanders, whose politics are more in line with those of the young progressives, but whose age is not. And atop the heap was Joe Biden, a Washington fixture and Democratic weather vane for nearly half a century.

Nonetheless, Harris is still aiming to represent the Democratic future. She has abandoned the more centrist leanings of her earlier career. Stressing her heritage (both Black and Asian), her geography (San Francisco, not Scranton), and her policies, she has sought to capture the new wave of Democrats. She put forward a Medicare for All plan to the right of Sanders but the left of Biden. She has supported decriminalizing border crossings, marijuana legalization, and the Green New Deal. These shifts were not enough to win the affection of the party’s left wing, though they might serve as a bridge of their own between Biden Democrats and the progressives.

This makes the stakes of the debate higher for Harris than for Pence. There’s very little that Pence can do or say that will change anyone’s views about Donald Trump. The president’s support seems locked in. Harris’s performance is unlikely to drive massive shifts in opinion, either. But a strong performance could help reassure voters who are undecided but leaning toward Biden, or who are deciding whether to vote at all, while a weak performance could scare them off. More important for her, though, it’s a major turn in the national spotlight—one that could help determine her future, and her party’s.

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