Huge fundraising powers Democrats’ hopes to flip the House | CNN Politics

Democrats are in striking distance of not one, but two red-tinted seats in Iowa .

Vice President Kamala Harris has fueled a fundraising revolution that is changing the game for down-ballot Democrats .

Republicans have had to buckle down on defense, keeping them from truly competing in once-feasible places like southwestern Connecticut , the Nevada suburbs and southeastern Pennsylvania .

Democrats need to net just four seats to flip the House .

Republicans are being outspent at the top of the ticket, says Nebraska Rep. Don Bacon .

The party went up on TV early in GOP -held seats, forcing GOP outside groups to narrow their own offensive opportunities.

GOP groups decided not to compete in once-competitive turf, such as the seats of Democratic Reps. Angie Craig in Minnesota , Nikki Budzinski in Illinois and Hillary Scholten in Michigan .

Republicans privately believe they are likely to lose at least two incumbents in the blue states.

Democrats fear Rep. Yadira Caraveo of Colorado is particularly vulnerable.

Republicans are feeling hopeful about heavily Hispanic seats in Colorado , New Mexico and Texas .