While Barack Obama and Hillary Clinton were busy throwing elbows Tuesday night, voters in Clinton's home state pushed Democrats an inch closer to an important milestone. Democrat Darrel Aubertine, a state assemblyman, surprised political observers by winning a northern New York State Senate seat in a special election over Republican William Barclay, whose father, the New York Times reported, once held the same seat.

The Dem pick up in this special election, made necessary by a Republican incumbent's retirement, puts the GOP in the tenuous position of holding just a 32-30 seat advantage in the legislature's upper chamber, and marks the party's seventh loss in recent years. Though a state senate seat may not sound terribly important, control of the upper chamber will be critically important when the state undergoes redistricting in two years, as we wrote in August.

After 2010, representatives of the Governor, the Assembly Speaker and the State Senate President will meet to redraw congressional and legislative district lines. Democrats hold the governor's mansion, though incumbent Eliot Spitzer will have to seek re-election in 2010, and own a wide majority in the Assembly. Taking back the Senate would put control of redistricting entirely in their party's hands.

Should that happen, not only will Democrats be able to redraw Senate borders to help their party win a new majority there, they will also be able to redraw Congressional borders and endanger some of the state's six Republican delegates to Washington. New York will lose two seats next year, meaning at least a few members of Congress will be forced to run against fellow incumbents.

If Democrats control the process, they will likely force Republicans together, or into districts that overwhelmingly favor the Democratic incumbent. The party will also be able to draw new Democratic voters into seats they hold tenunously, including those of freshmen Reps. Kirsten Gillibrand, John Hall and Michael Arcuri.

Republican seats currently held by Reps. Jim Walsh, who is retiring, John McHugh, Randy Kuhl and Tom Reynolds could be in danger. All three represent upstate New York, where Democrats have seen a resurgence and have captured both legislative and Congressional seats in recent years. Democrats also might be able to draw borders that weaken Republicans Vito Fossella and Peter King, who represent Staten Island and Long Island, respectively.

All sixty-two state senate seats are contested every two years, giving Democrats two more opportunities to snag victories in the chamber. They only need one seat to do so, as well: Lieutenant Governor David Patterson, a Democrat, would cast any tie-breaking votes.

National organizations favoring both parties, the Democratic Legislative Campaign Committee and the Republican State Leadership Committee, consider the Empire State Senate a top priority, and competitive races there typically cost millions of dollars. And Senate President Joseph Bruno told the New York Post that he's not giving up without a fight.

Before redistricting comes, huge amounts of resources will be devoted to keeping or capturing one seat in what has become one of the most crucial battlegrounds in the country.