Washington (CNN) - Democrats racing to protect their congressional seats also face a serious battle on their other flank: state capitals. One analyst has found that a quarter of state legislatures are in play this November, with the vast majority of the bodies at risk controlled by Democrats.
"I've been doing this for five cycles now and already we have the most chambers in play as basically at any point, going back to 2002," said Lou Jacobson, who writes for PolitiFact and recently completed an extensive analysis on state legislatures for Governing magazine.
"The other really striking thing," he said, "is this (election) is the biggest differential between the two parties."
Jacobson estimates a quarter of all state legislative chambers could see a change in power from one party to another this year, and that 21 out of 25 of those are chambers are now controlled by Democrats, but could switch to Republican hands after the election. Four chambers are currently Republican and could move Democratic.
He believes those numbers will grow.
"Usually the pattern is that the further you go along in the cycle that the figure starts to rise," he told CNN Radio. "So we're already starting out at the highest point (in recent memory) and it will probably only go up from here in terms of chambers in play."
Jacobson believes his is the only published handicapping of the battle for state capitols in the country.
He admits his results are not based on polling. With thousands of races involved, the elections analyst instead relies on one-on-one interviews with approximately 100 contacts in state capitols and inside the political parties.
Jacobson will update his assessment twice more before the election.
His first take on 2010 lists these chambers as potential takeover scenes, with an indication of which way he believes the chamber leans right now:
Leaning Democratic: Colorado House and Senate, Delaware House, Iowa Senate, Maine Senate, Michigan House, Minnesota House, Nevada Senate, North Carolina House and Senate.
Tossups: Alabama House and Senate, Alaska House, Iowa Senate, New Hampshire House and Senate, New York Senate, Ohio House, Pennsylvania House, Wisconsin House and Senate.
Leaning Republican: Alaska House, Indiana House, Montana Senate, Tennessee House and Senate. }