The California Democrat wielded the gavel during debate Friday, gave an Academy Award-length thank you address to the chamber and was casting what could be one of the more important votes of her 13-year congressional career.
The Senate on Thursday confirmed Tauscher, who represents the San Francisco suburbs, as undersecretary of state for arms control and international security.
In an emotional speech on the House floor, she said she had told House Speaker Nancy Pelosi, D-Calif., and Gov. Arnold Schwarzenegger, R-Calif., that she would resign when votes ended Friday.
That meant she could make a critical vote in favor of a Democratic bill to curb global warming and promote cleaner energy. With the Democratic leadership scrambling to come up with a winning margin, Tauscher's vote was essential.
She also told colleagues that on Saturday, she was getting married. "It's hard to be a blushing bride at my age, but I'll do my best," the 57-year-old said.