As paradoxical as it seems, though Ralph Nader will probably receive significantly fewer votes in his independent candidacy for president than he received in 2000, he could again easily make the difference in this year’s race.

In 2000, the consumer activist got 2,882,955 votes, 2.7 percent of the 105,405,100 votes cast. This time, even if he were to win just a quarter, even a 10th of the vote he got last time, he could still be the deciding factor. Why will Nader lose votes this year? Although the country was as highly polarized then as it is now — between Democrats and Republicans — the George W. Bush of 2000 was a far less polarizing figure than he is today.

And this time, voters perceive significant differences between the candidates. Traveling tens of thousands of miles across the United States, meeting thousands of people in every corner and in most of the 50 states, I have yet to find a single American who didn’t believe that George W. Bush and John F. Kerry would be very different presidents, taking the country in different directions. Half believes that it is very important to re-elect Bush; the other half believes it equally important to replace him. Some of the latter are enthusiastic about Kerry, but for most in this half, it is “Anybody but Bush.”

It is precisely this emotion — and the newfound appreciation for just how close a presidential election can be these days — that tells me that Nader will get significantly fewer votes this time.

Having said that though, look at the Florida election results from 2000. Nader received 97,488 votes in Florida; the margin between Bush and Al Gore was 537 votes. The Voter News Service national exit poll showed that had Nader not run, 47 percent of his voters would have cast ballots for Gore, while only 21 percent said they would have voted for Bush. (Thirty percent said they would not have voted.) If Nader had received only 2 percent of the votes he got in Florida and we assume the remainder of votes broke according to the VNS model, he still would have tipped the election to Bush.

Although Florida was the only state where Nader’s candidacy demonstrably made the difference, his presence came reasonably close to making a difference in 10 more. In New Hampshire, for instance, Bush carried the state by 7,211 votes, and Nader received 22,198 votes. Had Nader not been in the race — and had his voters broken 47 percent for Gore and 21 percent for Bush as the Voter News Service polls suggest — Bush’s margin of victory would have been only slightly more than 1,000 votes.

Nader almost cost Gore the electoral votes of six states. Gore’s narrowest numerical margin was in New Mexico, which he carried by just 366 votes. Nader got 21,251. A few more Nader voters would have spelled defeat for Gore.

In 2000, the Gore campaign strategy was pretty much to ignore Nader and hope that he would just fade away — and his vote did in fact diminish as the election drew near. But not enough for Gore to win.

This time, the signs are that the Kerry campaign and Democrats are going to be more aggressive with Nader, challenging election petitions in an effort to keep him off the ballot in some states, running advertising with the theme of “don’t throw your vote away” in others. It’s a good bet that a recent news story suggesting that Nader’s campaign was running afoul of federal laws by using the facilities of a tax-exempt, nonprofit organization originated from Democrats eager to besmirch Nader’s “Mr. Clean” persona.

In this election year, in which everything points to a close race, every little thing could be decisive, and Nader stands near the top of the list of things that may matter.

Charles E. Cook Jr., based in Washington, D.C., is editor of the Cook Political Report and an analyst for NBC News