Their trial hasn’t even begun, and already lawyers for three same-gender couples suing the State of Minnesota for the right to marry are fighting to keep their case on track.

In May, the three couples – Duane Gajewski and Doug Benson, Lindzi Campbell and Jesse Dykhuis, John Rittman and Tom Trisko – filed suit alleging that the state law prohibiting state recognition of same-sex couples violates their civil rights. Unlike other high-profile court battles in Iowa and California, the couples are working without support from most of the state’s LGBT leaders, who largely support an attempt to repeal the offending law in the next session of the legislature. In a statement issued when the couples filed their suit, OutFront Minnesota said they worried that “[a]nother judicial opinion reinforcing the discriminatory ruling of Baker v. Nelson (a 1971 Minnesota Supreme Court decision holding that same-sex couples were not entitled to seek marriage licenses) would set back progress in achieving justice for our families.”

Yesterday, Judge Mary DuFresne heard arguments about the Minnesota Family Council’s ability to intervene in the lawsuit on the side of the state – essentially, whether or not they could become another defendant in the suit. According to Martha Ballou, a lawyer for the couples, a successful intervention by the Council could spell doom for their case.

This would drag the case out as lawyers for plaintiffs assembled and argued a piece-by-piece rebuttal of the MFC’s many claims that same-gender marriage will lead to the downfall of “traditional marriage,” as in the famous Perry v. Schwarzenneger case that struck down California’s Propposition 8

“It would distract the court from they key issue of how gay people are being harmed” by the marriage ban, Ballou explained, because their lawsuit is built on a challenge to the ban’s constitutionality, not a rebuttal of the MFC’s claims about the harm done to society by same-gender marriage.

Perhaps more importantly, the suit could drag out beyond the plaintiffs’ ability to pay for it. The couples have set up a non-profit to help gather donations to pay for legal fees, currently estimated at $30,000 to $60,000 according to the organization’s website. The website describes this as “a generous discount from the going rate.”

If the MFC is allowed to join the case, according to another lawyer for the couples, Jason Schellack, “there will be lots of evidentiary hearings to decide what experts the Family Council can and cannot bring in. It could cost the plaintifs a lot of money” beyond the current estimate.

A decision is not expected immediately, although the couples’ lawyers say they hope Judge DuFresne rules on the intervention question before a December hearing of a petition for dismissal filed by the state. Still Ballou and the other lawyers were upbeat about their chances for success.