While most of the attention paid to November's election is focused on the presidential race and Mitt Romney's unprecedented comeback, control of the Senate is also up for grabs.
Several Senate races exemplify the complicated math of legislating.
In Maine, neither the Democrat or the Republican is faring well in the fight over retiring GOP Senator Olympia Snowe's seat. Democrat Cynthia Dill is far behind Republican Charlie Summers, and they both trail independent former governor Angus King, who is pulling in nearly 50 percent support in the three-way race.
Part of the reason Dill is doing so poorly is because the Democratic National Committee has refused to support her. King is expected to caucus with the Democrats, so a win by King is an effective win for them.
This had led to odd bedfellows, as Republican groups have been giving money to Dill, hoping she'll siphon off votes from King, though it's doubtful that she can grab enough to let Summers win.
In Missouri, Democrat Claire McCaskill is in a tight race against Republican Todd Akin, of "legitimate rape" fame.
Akin had been polling well against McCaskill until, in an interview, he claimed that a woman who has been raped can't get pregnant, insinuating that any woman who does get pregnant wasn't actually raped, a crackpot theory that has been thoroughly debunked by doctors and the medical community.
In response to his comments, the Republican National Committee pulled all his funding. Yet Akin is still in the running, demonstrating hoe conservative parts of Missouri continue to be. National Republican will soon decide if they can risk supporting Akin again, weighing a one-seat pickup against bad publicity.
And in Massachusetts, Democrat Elizabeth Warren has a narrow lead over incumbent Republican Scott Brown.
The race has been contentious. While both candidates have a "no negative ads" agreement, their supporters do not, and taunts about Warren's alleged affirmative action half-truths or Brown's spread in Cosmopolitan magazine permeate the battle for the seat of the late Ted Kennedy.
Whichever party wins the presidency will need to deal with a Republican House of Representatives, but could have either a strong ally or a resistant for in the Senate. Due to supermajority requirements and filibuster privileges in the Senate it is also possible that the president would have to handle a friendly Senate that still will not pass any of his legislation.