Dot-com millionaire Maria Cantwell, a Democrat and former RealNetworks executive, hoped against hope of unseating incumbent Republican Slade Gorton, known as the Senator from Microsoft for his relentless support of the software giant.
With roughly 1 million absentee votes still uncounted, the race was too close to call Tuesday. Early poll results pointed to a victory for Cantwell, but by Wednesday morning Gorton had slipped ahead, gaining an edge of about 3,200 votes.
Election officials predicted that it will take more than a week to declare a winner.
Gorton, 72 and a three-term Republican, has thrown his unwavering support behind Microsoft in its antitrust battle with the Justice Department. Microsoft was ordered to split into two companies after losing the trial earlier this year.
Cantwell has said she is against the breakup of Microsoft. Nonetheless, a defeat for Gorton could prove to be a setback for the software giant. Gorton has pledged to push for the appointment of a new attorney general to dismiss the case.
The GOP's slim majority in the Senate also hangs on the outcome of the race. If Gorton wins, the party will hold onto a 51-49 edge, effectively beating back a Democratic charge that saw the party pick three Senate seats. Democrats ousted Republicans in Florida, Delaware, Michigan, Minnesota and Missouri but lost seats in Virginia and Nevada.
In the case of a 50-50 split, control of the Senate would fall to the party whose candidate wins the presidential contest. Tie votes in the Senate are decided by the vice president, giving the winning presidential party the edge in any decisions that break along party lines.
Members of the high-tech community say both candidates have played an important role in pushing for laws that benefited the industry.
"Both candidates are capable and have proven records in supporting high-tech in Washington state," said David Brotherton, a spokesman for Seattle-based RealNetworks.
After losing her congressional seat in 1994, Cantwell, 42, joined start-up Progressive Networks, becoming one of the company's first 10 employees. Within five years, that company evolved into RealNetworks, now Microsoft's chief competitor in the market for Internet audio and video players.
Along the way, Cantwell became a multimillionaire. She funded her campaign spending with nearly $10 million of her RealNetworks stock, allowing her to turn down contributions from special interest groups.