An increase of independent voters in key battleground states could affect the election, according to a Bloomberg News analysis.
That is a problem for Democrats, who have lost the most voters in those states.
The ranks of indepdendent voters have grown in Colorado, Florida, Iowa, Nevada, New Hampshire and North Carolina by a total of 443,000 since 2008.
Democrats have lost 480,000 voters in the six states while Republicans have gained 38,000 voters.
Michelle Diggles of Third Way, a political research group, told Bloomberg News that independents are really just fed up with both parties.
That may be true. But if the analysis is correct, a surge toward independence may set Democrats back while benefiting Republicans.