JEFFERSON CITY, Mo.  – For Missouri Democrats, Tuesday’s fight over seats in the Missouri General Assembly is about one thing: beating back Republican supermajorities.

Still, when Missouri voters head to the polls at 6 a.m. on Tuesday, nearly a third of the seats in the Missouri House and more than half of the state Senate seats up for grabs will have already been decided. Republicans are expected to prevail with at least majorities in both chambers of the General Assembly when polls close 13 hours later, and they are fighting to maintain their supermajorities.

They start with an advantage. As one Democrat put it Monday night, the advantage is “baked into the cake” with districts that often favor one party, mainly Republicans.

By the time the first votes are cast, Republicans will have won back almost half of the 17 seats up for grabs on Tuesday. In nine Senate races Tuesday, the Republican is not facing an opponent — including two open races. In one case, all Republican Dan Hegeman had to do to win a seat in the Missouri Senate was sign up to run (he faced no primary or General Election opponent).

In the two Senate seats being vacated by Democrats – one featuring Democrat Ed Schieffer against Republican Jeanie Riddle, and the other featuring Democrat Jeff Roorda against Rep. Paul Wieland – both are trending Republican. But in the seat being vacated by Sen. John Lamping, R-St. Louis, Democrats are putting up a fight behind Jill Schupp’s effort to defeat Republican Jay Ashcroft.

Republicans currently have a 23-vote supermajority (the minimum votes required) in the upper chamber. If they win the two open Democratic seats and lose one seat currently held by a Republican (the Lamping seat), their majority could still grow to 25.

In House races, Republicans – who have a 110-vote supermajority in the lower chamber – will start the morning by winning back 43 of the chamber’s 163 seats by their candidates simply having their name on the ballot.

Republicans are targeting about eight of the 53 seats currently held by Democrats, while Democrats have focused their attention on about ten seats held by Republicans.

Democrats feel confident that their candidate, Deb Lavender, will emerge the victor in the St. Louis House seat being vacated by House Budget Committee Chairman Rick Stream and that they could win the seat formerly held by Rep. Myron Neth. But Republicans feel equally confident that they will pick off at least one or two of the seats currently occupied by Democrats.

By the numbers, it is not clear how much further Republicans can stretch their majorities. This cycle, after years of Democratic malaise from losing their majorities more than a decade ago, Democrats have begun to at least put up a fight. They have strengthened their organizational and fundraising efforts, and in races where Democrats do not typically play, this year they did, aiming big money to help them with research and data to criticize their opponents and target possible voters.

Republicans have turned to the well oiled political machine that is the House Republican Campaign Committee to help its candidates in challenging races, spending thousands to help Chuck Base, for example, in his attempt to beat Democratic incumbent John Wright.