The Gillibrand letter urges supporters to help the campaign meet a $100,000 fundraising goal by March 31. Gillibrand's campaign has more than $8.1 million in the bank for her reelection, while Turner has less than $100,000 in his House account, which can be transferred to a Senate campaign.

"We need to show right-wing Congressman Turner and her other extreme opponents that Kirsten is no push over," wrote Lillian Choi, a Gillibrand campaign aide.

Choi has played the attack-dog role for Gillibrand before, particularly when it comes to women's issues. When racy blog posts about sex and drugs were discovered on the website of Marc Cenedella, a Republican businessman who had been challenging Gillibrand, Choi sent a similar email labeling the posts "obscene, offensive and sexist."

"This kind of garbage isn't suitable for any office, let alone one of the highest offices in the land," she wrote.