National polls are meaningless at this stage in the election

One would think that Gallup, Pew, Rasmussen, every sufficiently wealthy news organization and anyone else interested in conducting a poll would be familiar with the basics of the American electoral system. Why they all insist on continuing to waste precious ink on national polls, then, is completely mystifying.

Gallup's latest poll of registered voters reports that former Gov. Mitt Romney and President Barack Obama are tied nationally, 48 to 48 percent. Gallup's latest poll of likely voters, based on a complex set of assumptions about voter turnout, has Romney leading Obama by 5 percentage points, 51 to 46.

These figures are based on a national sample, so they theoretically include voters from Ohio, Florida and Virginia. They also include voters from Wyoming, California, Alabama, Delaware and about 40 other states whose voters could not possibly be any less relevant to the outcome on Nov. 6.

At this stage in the election, like any sufficiently close election, the fate of the candidates rests with fewer than a half-dozen states. The continuing snapshots of national polls are useful for pollsters and academics, who are interested in things like expected vote share or the probability of victory in the national popular vote. Most stakeholders care only about the likelihood of victory in the Electoral College, and a national poll is not very useful at this point.

This is why most prognosticators consider Obama to have a far higher chance of victory than the national polls would suggest. The Signal has Obama at a 65 percent chance of victory, while Nate Silver gives him a 75 percent chance against Romney. A small, demented chorus of observers has recently dinged Silver for this conclusion, citing various gut feelings to the contrary.

Sources: Betfair, Intrade, IEM, HuffPost's Pollster and RealClearPolitics

Any way you slice it, Obama is leading in states that account for well over 270 electoral votes. As we've said a million times before, Obama needs only Ohio, Florida or Virginia to prevent Romney from reaching 270 electoral votes in most scenarios. Romney needs all three.

Romney maintains a slight lead in aggregations of many polls. HuffPost's Pollster listed six new polls on Monday, and Obama led in only one. Romney led in three of these, and two were are tied. Pollster, which has a very transparent method of aggregation, combines all recent polls and has Romney up 47.4 to 47.2. RealClearPolitics, which aggregates polls with a completely opaque method, has Romney up 47.6 to 46.7.

If you are a poll junkie and you need your latest fix, I suggest following the latest polls in Florida, Virginia and Ohio. If you are still obsessing over national polls, I suggest you brush up on the Constitution. Just in case, here's a link. It's free.

Follow the state-by-state and overall presidential predictions in real time with

David Rothschild has a Ph.D. in applied economics from the Wharton School of Business at the University of Pennsylvania. Follow him on Twitter @DavMicRot.