Democratic challengers raised more money than Republican incumbents in 20 competitive House races from California to Virginia during the first three months of the year. President Obama's party also has the upper-hand in eight other districts where congressmen are retiring.

The early look at fundraising, laid out in reports filed with the Federal Election Commission, suggests momentum may be with the Democrats, at least for now, as the party tries to wrest control of the House from the GOP.

How much money individual candidates have raised so far this year provides only a slice of the broader campaign finance picture.

Democrats say the totals are a clear sign of momentum. Republicans say GOP members have more money in the bank and will have all they need in November.