In the most competitive 94 districts, Democrats have booked over $177 million in ads since Sept. 1, while their GOP opponents have booked $93 million, according to a POLITICO analysis of advertising data. Republican outside groups have partly made up the difference, but the party is still bracing for a string of defeats next month.

“At this point, it’s pretty clear there’s going to be losses. The question is just how many, and if Republicans can keep it in the mid-to-high single digits,” said Ken Spain, a GOP strategist and former communications director for House Republicans’ campaign arm. “The money and the momentum is so significantly one-sided.”…

Democratic candidates have spent at least twice as much as Republican candidates on TV in nearly four dozen districts, according to data from Advertising Analytics, a media tracking firm. That edge is particularly noticeable in open seats. In southeast Iowa, Democrat Rita Hart has spent nine times more on TV than her GOP opponent. On the South Shore of Long Island, Democrat Jackie Gordon has spent $1.7 million on ads, while Republican Andrew Garbarino has spent less than $100,000. And in suburban Houston, Democrat Sri Kulkarni has aired $2.7 million worth of ads, six times more than his Republican rival.