Four surveys conducted in late July reveal close races in open seats in Oregon, Colorado and California that President Joe Biden carried by between 11 and 15 points in 2020. Taken all together, GOP operatives view the data as a sign that Biden’s sinking approval numbers could drag Democratic candidates down enough to bring deep blue turf into reach.

The voter registration and partisan lean of the districts all strongly favor Democrats, and it will be a heavy lift for Republicans to flip any of these seats. Moreover, the only polling available in the districts are internal Republican figures, which can sometimes be rosier than reality for the party…

The most encouraging poll for Republicans came in Oregon’s new 6th District, where Republican Mike Erickson led Democratic state Rep. Andrea Salinas by 7 points, 47 percent to 40 percent, with 13 percent undecided. In a district that Biden won by nearly 14 points, his approval rating is underwater by 20 points. Republicans lead on a generic ballot by 7 points — a rough reality for a seat that Democrats drew to be safe.