FORTUNE -- The Democrats have a lot riding on Sen. Susan Collins (R-Maine.) The low key, pragmatic New Englander is shaping up as the go-to Republican vote on the Wall Street reform bill.
Early Friday morning, lawmakers hammered out a final version of the bill. Collins is expected to be one of a few key Republican lawmakers to approve the legislation when Congress votes next week.
If the massive overhaul is ultimately successful in leveling the economic rollercoaster, Collins, a former financial regulator herself, will be lauded for skillfully deflecting pressure from her own party and working in a bipartisan manner to put her country on better financial footing.
However, should the legislation fail to hit the mark, Democrats will likely alienate one of the last centrist conservatives in the upper chamber who is still willing to cut a deal and break with GOP leadership. Collins could also find herself in a tough spot defending her decision with voters in the traditionally blue state of Maine.
Collins has a vested interest in getting regulatory reform across the finish line. Maine's jobless numbers are bleak, but better than the country's overall -- the state had an 8% unemployment rate in May. But an even greater reason for her to play a key role in reforming the financial system is the state's impressive statistic of being one of seven states to avoid having a single bank failure. In fact, TD Bank is a key job creator for the state. Headquartered in Portland, Maine, the banking and financial services company is one of the 35 largest commercial banking companies in the U.S.
Securities and investment firms also rank among the top three industries bankrolling Collins' campaign coffers. In the past five years, banks and other financial firms have contributed more than $400,000 to Collins. New York-based investment firm Elliott Management is her third-largest contributor, behind General Dynamics and Marriott.
Collins has asserted her independence throughout financial regulatory reform negotiations, first as the only Senate GOPer to refuse to sign a letter opposing a vote on the Democratic proposal. Then in April, she was one of only four Republican senators to vote in favor of the Senate's Wall Street reform legislation. And even more recently, Collins has risen above the fray as a must-have vote for Senate Democrats to move ahead with the bill they expect to pass next week.
Collins got what she asked for on financial reform. The Senate-passed bill included an amendment she sponsored that requires strong capital requirements for financial institutions. Collins also pushed for a council of regulators in an independent bill that was incorporated in the overhaul.
Her Republican colleagues have not taken kindly to Collins embracing the Maine state logo, "Dirigo," which means "I lead" in Latin. After the stimulus vote, Collins publicly noted how her role in the negotiations had taken a toll on relationships with her GOP colleagues. "It is very hard," she said. "These are my friends. I work with them every day. I believe I have done the right thing, but there is a cost, there is a definite cost."
But that doesn't stop Collins from inserting herself into the center of controversial votes. Over the years, Collins has bucked the party line on a range of issues such as taxes, health, environmental policy and the budget. In 2005, she gained notoriety as a member of the 'Gang of 14,' which forged a compromise on the use of judicial filibusters.
More recently, as the number of moderate Republicans in the Senate has dwindled, Collins has received attention from Democrats as a centrist that they can work with. Last year, Collins made her mark over the stimulus project after President Obama courted her for her vote. Working in tandem with fellow Mainer Olympia Snowe (R), the two wielded an inordinate amount of power in shaping the final package, which only went through after nearly $100 million was cut from the House bill.
At the time, Collins said, "This crisis is extraordinary, and my constituents don't expect me to stay on the sidelines... They expect me to jump in. People don't want us to be the party that says no, just no."
At the outset of the latest financial regulatory reform process, Collins made it a point to cite her bona fides as a former financial regulator for Maine -- she served for five years as Commissioner of the Department of Professional and Financial Regulation in Maine before being appointed New England regional director for the Small Business Administration by President George W. Bush. Collins has made it clear that she understands Wall Street reform better than most.
Mainers have rewarded Collins for her independent streak. The last election cycle, when President Obama garnered 58% of the vote in Maine, was a particularly tough one for GOP candidates.Yet Collins was reelected with 61% of the vote.