One thing you hear that might be in the context of horseshoes is that the vice presidential debates don't matter. They do. They give us a chance to look at the one staff choice the noinee has made, and in some cases, they can begin something in the dialogue that manifests itself later.
I think I've watched every one of them. Here is my take:
1976 – although in his 1974 reelection campaign, Dole began a process to become less the hatchet man he had been perceived of being as RNC chair, his nastiness came out in the debate when he somewhat coldly proclaimed that every war of the century had been started on the Democratic Party's watch, in one sense suggesting that a weakness on defense issues on the part of the Dems had left the country weak. World War II ws a Democrat's war. I didn't put that in quotes but I'm pretty sure he specifically said that. Now, I know now from knowing more about the last Republican I would have considered voting for (in 88, not 96) that he was bitter about that war, that he didn't particularly want to go and that it ended for him a very realistic dream of becoming a physician because it rendered one of his arms useless. He became a lawyer instead, and from there a US Rep and then Senator. But the statement began to reverse Ford's lead and in particular did so on matters of foreign policy and defense, preparing the way for Ford to declare that the Soviets did not dominate Eastern Europe. In the VP debate, Dole also indicated how gotcha narrow he ahd his fellows in the GOP were when he sniggered at Carter sitting down for a Playboy interv iew, and quipped, “We'll concede you the bunny vote.” Note that the margin of victory was roughly the magazine's circulation.
1980 – There wasn't one. There was only one presidential debate. Carter didn't want to debate both Reagan and Anderson, and the League of Women voters kept Anderson in until his numbers dropped below 15 percent in the polls.
1984 – This was the first step towrd me loathing Bush, in which he said he “kicked a little ass” by aggressively going after Geraldine Ferraro re her husband's business. Barr had also referred to her as a “rich bitch.” It is possible that this debate indicated Ferraro was not ready to be president.
1988 – This one backfired. Bentsen said to Quayle that “you're no Jack Kennedy.” This was looked at as rude in part because of the rapid spin machine Lee Atwater exploited. My least favorite election and it produced my least favorite president. I hope against that Atwater can still feel the maggots eating at his intenal organs.
1992 – This one crushed the Perot campaign because it looked cruel to have tapped Stockwell as his running mate. It also cemented that Quayle was in over his head.
1996 – This one was kind of pointless. It pitted Artifice Al against a man the GOP had been hailing as an intellectual because it said he had provocative ideas. (Not hating ne-gros because they may one day be your offensive line qualifies as an idea in the GOP universe. And no one really sorted out to what extent Kemp's tax ideas had been a disaster as practiced by the Reagan admin.)
2000 – I frankly think that Lieberman threw this one. He definitely so deferred to Cheney that people who he seemed reassuring, a grown-up, benign, the kind of guy who could make up for W's inexperience on international / security / defense stuff. Lieberman did nothing to expose cheney for what he was.
2004 – This one was pretty pointless, but as in 96 I wasn't crazy about the our guy. I think if you were undecided youc ame away not thinking of Edwards as more than a talented speaker.
2008 – Palin was already a known quantity, but the debate was consistent with the covnentional wisdom. It was clear that Obama had made a good choice.
That the vice presidential debates haven't been game changers doesn't mean they lack meaning. They contribute to the perception of the presidential candidates and most of the time, they have contributed to a narrative that would result in votes.