Undecided voters–"or, as I call them, morons," Bill Maher says–remained a stubborn five or six percent of the electorate as the polls reported final results yesterday. Obama and McCain each have spent tens of millions on TV ads to persuade them, and thousands of hours of door-to-door canvassing to talk to them face to face. 

What’s their problem? The undecideds have been staring at the menu now for almost a year–why haven’t they made up their minds?

In fact the "undecideds" include at least four different groups

— 1. The cross-pressured: people with conflicting political interests–upper-class white women from Republican families who are pro-choice; older white union members who don’t want a black president.

— 2. The cynical and alienated: people who say "all politicians are alike; they’re all liars; the system is rigged."

— 3. The inattentive and the ignorant: people who don’t pay attention to politics, who say they aren’t interested.

— 4. The deceivers: people who really have decided–but won’t tell the pollsters.

Each of these groups is likely to follow a different trajectory today:

The cross-pressured are the principal target for both campaigns, but for at least some of them, economic pressures push them towards Obama.

The cynical and alienated are likely to vote for a third party, or not at all.

The inattentive and ignorant may be moved by the enthusiasm and passion of the Obama campaign and its focus on the economy and health care.

The deceivers seem to me to be more likely to be secretive McCain supporters than Obama people.

So today it’s hard to see any decisive movement one way or the other from the undecideds, but we may see some movement towards Obama.

Nevertheless, their votes could be crucial in states where the leading candidate had less than 50 per cent in the final polls. In Florida, for instance: Pollster.com, which aggregates the poll numbers, ended up with Obama at 48.3 and McCain at 46.1. That means 5.6 of likely voters were undecided the weekend before Election Day. If 71 per cent of the Florida undecideds went for McCain, he’d win 51.1 per cent of the popular vote – and of course all of Florida’s 27 electoral votes.

The situation is similar in the final polling for Ohio, Indiana, Missouri and North Carolina, where Obama is ahead but didn’t reach the 50 per cent mark.

Still, there’s nothing that requires the undecideds to make up their minds. Despite the tens of millions the campaigns have spent to win their votes, many will probably stay home today. If that happens, Obama probably wins most of the swing states, where he was ahead in the final polls.