The Wall Street Journal notes that "widely divergent poll results in recent days underscore a paradox of the 2004 presidential race: Despite all the surveys, it may be the toughest election in memory for anyone to track."
The main reasons "range from growing reluctance" for citizens "to participate in surveys to increasing reliance on cellphones rather than the land lines pollsters have long used to ensure demographic and geographic balance in surveys.
"But this year's bitter presidential contest has heaped on new challenges. They include an exceptionally close race and a polarized electorate that magnifies the consequence of different polling methods. In addition, unprecedented voter-mobilization drives by both parties make it especially tough for pollsters to say which voters probably will show up on Election Day."