Former President Bill Clinton has more potential to help Democratic candidates like U.S. Senator Michael Bennet at campaign events than does President Barack Obama, according to a new Gallup poll, which shows Clinton also has “significantly more positive impact” than Obama among independents and even Republicans.

Late last night, Clinton appeared at the Evie Garrett Dennis school to urge roughly 2,000 would-be voters to back Bennet, who is facing a tight challenge from Republican Ken Buck. Clinton blasted outside interest groups for their attacks on Bennet. “There’s a reason they got phony names and don’t want you to know who they are,” Clinton said. “Because if you knew who they were, you would know why they pay for the ads and what they hope to get for it” (via the Denver Daily News).

Buck’s campaign takes a sarcastic shot at Clinton for first endorsing former state House Speaker Andrew Romanoff in the Democratic primary for Senate and now Bennet, who beat Romanoff. “We hope President Clinton’s second endorsement in the Senate race is just as successful as his first,” says Buck campaign spokesman Owen Loftus (via The Hill).