We report. You decide: Does President Bush owe his controversial win in 2000 to Fox cable television news?

Yes, suggest data collected by two economists who found that the growth of the Fox cable news network in the late 1990s may have significantly boosted the Republican Party's share of the vote in the 2000 election and delivered Florida to Bush.

"Our estimates imply that Fox News convinced 3 to 8 percent of its audience to shift its voting behavior towards the Republican Party, a sizable media persuasion effect," said Stefano DellaVigna of the University of California at Berkeley and Ethan Kaplan of Stockholm University.

In Florida alone, they estimate, the Fox effect may have produced more than 10,000 additional votes for Bush -- clearly a decisive factor in a state he carried by fewer than 600 votes.

Fox cable news debuted in 1996 as a competitor to CNN and four years later was available to about one in five Americans. That allowed DellaVigna and Kaplan to compare changes in the Republican vote share from 1996 to 2000 in 9,256 cities and towns where Fox News was introduced. They also examined election data from 2004. They found clear evidence of a Fox effect among non-Republicans in the presidential and Senate races, even after controlling for other factors including vote trends in similar nearby towns without access to Fox. "While this vote shift is small . . . it is still likely to have been decisive in the close presidential 2000 elections," they concluded.

DellaVigna and Kaplan say the Fox effect seems to be permanent and may be increasing. But they caution that their study does not prove that Fox is shading the news to favor Republicans. Their findings would also be explained if Fox is offering balanced coverage that counteracts lefty bias in competing media.