India, Aug. 27 -- Data centers, once welcomed by politicians of both parties as engines of jobs and tax revenue, have become a growing political liability for Republicans in the US heading into November's midterm elections, as rising electricity bills fuel a bipartisan backlash that analysts say cuts unusually deep into the party's most vulnerable House seats. An analysis of Data Center Map figures cited by Politico found that 40 of the 69 US House districts rated competitive this cycle have data centers either planned or under construction, with Republicans holding most of those seats as they defend a narrow five-seat majority.

The exposure is sharpest in Pennsylvania, where four Republican-held seats rated competitive by major forecast...