In Polls, Biden Gets a Hold

News media narratives tend to group horse-race developments into one of the three basic categories: win, lose, or draw. Sometimes, however, a political event falls into the awkward middle ground between those realms.

Thursday night’s vice-presidential debate in Danville, Ky., is a potential example of this. Instant polls conducted after the debate are suggestive of something between a tie and a modest win for Vice President Joseph R. Biden Jr.

A CBS News-Knowledge Networks poll of undecided voters who watched the debate found 50 percent giving the advantage to Mr. Biden, 31 percent to the Republican, Representative Paul D. Ryan, and 19 percent calling the debate a tie.

A CNN poll of debate-watchers, however, had 48 percent giving the debate to Mr. Ryan, and 44 percent to Mr. Biden.

The surveys are not directly comparable: the CBS News poll was conducted among undecided voters only, while the CNN poll was among all debate viewers. But it might be noted that Mr. Biden’s margin in the CBS News poll was somewhat larger than Mr. Ryan’s in the CNN survey, which was within the poll’s margin of sampling error.

The social media sentiment during the debate also seemed to flow along these lines. The liberals in my Twitter feed seemed a bit more satisfied with Mr. Biden’s performance than the conservatives were with Mr. Ryan’s, but it wasn’t a slam dunk.

Vice-presidential debates rarely move head-to-head numbers between the presidential candidates – even when there is a much clearer verdict in instant-reaction polls. So one should err on the side of caution in assuming that the debate had much influence either way.

There is a plausible hypothesis, however, that some of Mr. Romney’s recent surge in the polls reflects a growing “enthusiasm gap” between Democrats and Republicans. To the extent that Mr. Biden’s performance re-energized Democratic partisans, he may have left President Obama in a slightly better position than where he started the night.

Another hypothesis, not necessarily unrelated to the prior one, is that some of Mr. Romney’s gains in the polls are momentum-driven, and could include some soft support that might come up for grabs again once the news cycle turns over. We’ll have to wait and see how long the vice-presidential debate leads the news, as opposed to Mr. Obama’s poorly-reviewed performance last week in Denver.

The conventional wisdom about debates also sometimes evolves in a way that differs from the initial reaction to them. Instant polls of the first presidential debate in 2000 showed a modest lead for then-Vice President Al Gore — but it was his opponent, George W. Bush, who made gains in head-to-head polls after there was criticism of Mr. Gore’s demeanor.

My best guess: perhaps Mr. Biden can be credited with what in baseball statistics would be termed a “hold”: something a bit shy of either a win or a save and which will probably seem perfunctory with the passage of time, but which might have done his team a bit of good.

However, he won’t have relieved Mr. Obama of the burden of needing to improve his performance in next week’s presidential debate in Hempstead, N.Y.