Democratic Senate candidate Al Franken launched a counteroffensive Monday in the ongoing legal battle to determine whether he or Republican incumbent Norm Coleman won the November 2008 U.S. election in Minnesota.

Among other things, Franken’s campaign requested that state officials authorize him to be seated in the Senate, pending a decision in pending court proceedings on the disputed election outcome. That proposal — based on last week’s declaration by the state election canvassing board that Franken had narrowly defeated Coleman — was immediately rejected by both Gov. Tim Pawlenty , a Republican, and Minnesota Secretary of State Mark Ritchie, a Democrat.

The race was prolonged last week when Coleman filed suit challenging the results of the vote recount, certified by the canvassing board on Jan. 5, that showed Franken with a lead of 225 votes out of 2.9 million cast. Coleman, in his complaint, claims that election officials counted some votes twice, did not count some improperly rejected ballots and were not consistent in handling missing ballots during the six-week-long recount.

The Franken campaign responded to Coleman’s suit on three fronts.

First, it sent the letter to Pawlenty and Ritchie asking both officials to immediately sign the election certificate declaring him winner of the Nov. 4 race. Franken’s legal team argued there is precedent to seat a senator provisionally in the midst of ongoing legal challenges.

“Now that the recount is complete and the new Congress has convened, state law does not provide for further delay, and federal law requires that the certificate issue. Accordingly, we request respectfully that Mr. Franken’s election be certified by the close of business today,” the letter read.

Franken is unlikely to get his way on this point. Both Pawlenty and Ritchie responded by issuing statements denying his assertions and saying state law clearly forbids certifying election results until all legal challenges are resolved. That is likely to take a month or more.

Franken attorney Marc Elias did not, however, rule out the option of taking the issue before the state Supreme Court.

The Franken campaign is also ramping up its legal arguments for the impending election challenge. Called an “election contest” in Minnesota, the case will be heard by a three-judge panel appointed by Minnesota Supreme Court Justice Alan C. Page. On Monday, Page named two women and one man to hear the case: District Judges Elizabeth Hayden, a Democratic appointee, Denise Reilly, a Republican appointee, and Kurt Marben, an appointee of Independent former Gov. Jesse Ventura.

Page assumed the duty for appointing the judges after Chief Justice Eric Magnuson recused himself due to his involvement in the recount as a member of the state canvassing board. State election law requires a trial to begin within 20 days of the suit being filed.

The Franken campaign Monday filed its response and counterclaim to Coleman’s lawsuit, as well as a separate “petition to dismiss” document, claiming the suit attempts to raise issues beyond the scope of an election contest.

The suit, Elias said, “is riddled with errors that are fatal to much if not all” of its claims.

In its counterclaim, the Franken campaign is pushing for its own set of uncounted absentee ballots, which it says were wrongly rejected, to be included in the final vote tally.