No, not Nancy Pelosi, Hillary Clinton, Valerie Jarrett, and Christina Romer. Instead, the most powerful women in America might be the club of four Republicans in the United States Senate: Olympia Snowe, Susan Collins, Lisa Murkowski, and Kay Bailey Hutchison.
Snowe has voted with the Administration 91% of the time according to new Obama Support Score (OSS), the derivation of which I'll explain in a moment. This is, by some margin, the highest score for any Senate Republican and also higher than that of a handful of Democrats. Collins is second on the list, with an OSS of 72%, and Murkowski is fourth among Republicans at 70%. While Hutchison is further down the list, she is clearly angling to be a thought-leader in the GOP and is likely to be a wild card on certain issues, having voted with the administration, for instance, on SCHIP and the Ledbetter Fair Pay Act.