"I couldn't wait to thank you," wrote Gillibrand, who is up for re-election again in 2012, before she resumes the usual six-year schedule. "Our campaign just closed its books for the FEC filing period and I am proud to tell you that we have broken our all-time highest campaign record and raised over $3 million in the first quarter."

Gillibrand has always been a prodigious fundraiser--even during the many months she was derided as being "vulnerable"--so breaking her own record is saying something. (Update: Her previous high quarter, according to a spokesman, was $2.3 million in the first quarter of 2009, her first since being elevated to the Senate.)

And while it's never easy to discern what moves people to open their checkbooks, there are a few factors that probably helped her along.

In December, she got a raft of good press--including a couple front-page, above-the-fold stories in The New York Times--for her work on the 9/11 health care bill and for her efforts to repeal Don't Ask Don't Tell.

The Republican House probably didn't hurt either, as the incoming majority threatened to gut the health care bill and defund Planned Parenthood--issues that Gillibrand and other Democrats used to solicit donations, in order to better fight their new foil.

But, perhaps more than anything, donors--as a general rule--like to give to a winner, and Gillibrand's big victory in November, coupled with her highest-ever poll numbers and a lack of credible challengers who seem to be eyeing her seat, makes her a better investment than she has anytime since her appointment two years ago.

Here's the full email:

Dear Friend,

I couldn't wait to thank you. Our campaign just closed its books for the FEC filing period and I am proud to tell you that we have broken our all-time highest campaign record and raised over $3 million in the first quarter. I am astounded and humbled by the outpouring of grassroots support from all over New York.

Thanks to you, and the generosity of thousands of others just like you, we have given our potential opponents 3 million reasons to understand that a fight for our Senate seat won't be easy. This campaign will be a long and tough road, but we are off to a great start.

Your support and friendship continue to make all the difference.

Kirsten