Since a big part of the background noise of political talk about the elections has to do with undecided voters–who they are, how many there are, which way they are likely to “break”–thought it might be good to sort through the static even a bit more than I tried to do on Friday.

There are really two very separate question that tend to get conflated. The most commonly discussed is how “the undecided vote” (note the subtle suggestions of a coherent voting bloc in the very term) is likely to break in this election or every election. Some Republican spinners just invoke the ragged “incumbent rule” (an outdated and often oversimplified political science tenet holding that late undecideds invariably break against incumbents) and assume Mitt will get a last-minute surge. Others, with varying degrees of imprecision, attempt characterizations of the undecided vote (sometimes by confusing them with “independents,” a voter self-identification category that is endlessly confusing and that also currently leans Republican because of its popularity among many Tea Folk, and sometimes by relying on teeny-tiny subsamples of undecideds in larger polls) that also support predictions of a Mitt Surge. Most of these “analyses” can be safely ignored.

The futility of most of the arguments over the predilections of “undecideds,” in any event, can best be explained by looking at the second question: how many of these folk are there, anyway? I mentioned on Friday Nate Cohn’s estimates of the relatively low ratio of undecideds-to-mobilizable-base-voters (particularly for Obama, who is systematically doing better in polls of RVs than of LVs) in battleground states. But here’s political scientist John Sides with fairly definitive answers to both questions about undecideds, based on a consensus model of the evidence from past presidential elections:

The model predicts that these undecided voters will split almost exactly evenly: 50.1% for Obama and 49.9% for Romney. There is substantial uncertainty in this estimate, naturally. The 95% confidence interval for Obama’s predicted vote share is 44% to 56%.

A small number of other respondents (3%) indicated that they will vote for a third-party candidate. If we include them along with undecided voters—assuming that at least some third-party voters will end up voting for a major-party candidate—then the prediction is 52% Obama and 48% Romney. Again, the uncertainty means that this is not any real “lead” for Obama.

If we focus on those undecided voters who say they “definitely” will vote—this is about 58% of undecided voters— the balance tilts more toward Romney: 44% Obama vs. 56% Romney. As in polls more generally, Romney tends to do a bit better among self-described likely voters than among voters as a whole. (Again, insert caveat about uncertainty.)

However, consider the math here. Assume that only these likely undecided voters (the 58%) actually make it to the polls. You’ve got 56% of 58% of 6.5% voting for Romney and the rest for Obama. This would add at most 0.4 points—that is, less than half of 1 percentage point—to Romney’s margin over Obama nationwide. That is, if you assume the model is correct, that we can safely ignore the underlying uncertainty, that only these undecided voters will vote, and so on and on.

The lesson I draw from this analysis is: how the undecideds “break” may not be consequential in this election.

In other words, even a projection of the undecided vote that is quite favorable to Romney lifts him less than a half of a percentage vote nationally. Could this affect the outcome? Of course it could, but only in the sense that in very close elections everything could affect the outcome (as in Florida 2000, where I routinely responded to claims that Gore would have won had he “shifted left” to deny votes to Nader by pointing out the Social Workers Party candidate won more votes than Bush’s official margin in the state, and asked if anyone thought a few favorable references by Gore to Leon Trotsky might have done the trick?). As a guide to stretch-drive strategy, though, you hunt where there is the largest concentration of ducks, and aside from the extremely problematic proposition of how, exactly, to appeal to undecided voters, there just aren’t enough of them to make it the centerpiece of an entire presidential campaign (certainly for Obama, whose main strategic opportunity is to close the RV/LV gap as rapidly as possible).

Part of the confusion and heat that accompanies this question, of course, has to do with its perennial importance in long-term intraparty strategic arguments, since “centrists” in both parties always want candidates to focus on undecideds, while advocates of the party “base” always want them to be faithful to the converted but unmobilized voters. Some of the “centrists” urging Obama to issue a last-minute endorsement of Simpson-Bowles, for example, may do so because they sincerely think it will appeal to today’s undecided voters, but there’s little doubt they favor such an endorsement as an end in itself and also for purposes of “positioning” the Democratic Party where they want it positioned moving ahead. And there are similarly mixed motives among folk urging Obama to take a completely contrary tack.

You can’t take the politics out of politics, of course. But it’s worth noting that regardless of where you want your party to wind up four or ten or thirty years from now, or what you favor as substantive policies for the country, using theoretical (and undocumented) appeals to undecided voters to justify this or that last-minute message is singularly inappropriate for this particular election.

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Ed Kilgore is a political columnist for New York and managing editor at the Democratic Strategist website. He was a contributing writer at the Washington Monthly from January 2012 until November 2015, and was the principal contributor to the Political Animal blog.