The Wisconsin Supreme Court heard oral arguments Tuesday for a case that has the potential to overturn a 2006 constitutional amendment banning gay marriage and civil unions in Wisconsin.

With the lawsuit McConkey v. Van Hollen, University of Wisconsin-Oshkosh professor William McConkey is contesting the constitutionality of a 2006 referendum that denies same-sex couples the right to a legal marriage.

Lester Pines, McConkey’s attorney, stressed the importance of the case to the court, saying it could improve the rights of Wisconsin voters with respect to constitutional referendums.

He also said the 2006 referendum, which included an item that banned gay marriage and another that banned civil unions, was unconstitutional because it grouped together what should have been two separate amendments into one amendment.

“William McConkey … had a right to engage other voters and say, ‘OK, look, if you want to vote for the first question, I can’t persuade you not to do that, but I want you to vote no on the second question,” Pines said. “When those amendments were not submitted separately, his right to fully participate — which is really a speech right — was infringed.”

Wisconsin Assistant Attorney General Lewis Bellin said the lawsuit has the potential to “tie the hands” of the state Legislature and could make amending the Wisconsin Constitution much harder than necessary.

“McConkey is asking the court to change the standard for compliance with the separate amendment rule in a way that would make amending the Wisconsin Constitution extremely difficult,” Bellin said.

Bellin said to require every distinct proposition in an amendment to be interdependent upon all other amendments could make drafting future amendments very difficult for the Legislature, as it would constrict the Legislature so much that legislators would have to present amendments in such tiny bits and pieces that the process would become unworkable.

According to Bellin, McConkey must prove Wisconsin voters wanted to vote for one phrase of the proposed 2006 amendment and vote against the other to substantiate their claims in the case.

Bellin also said it is possible a decision in the case will not come until May, when the current session of the court will end.

Stacy Harbaugh, community advocate for the American Civil Liberties Union of Wisconsin, said she encountered voters who favored dividing the vote while campaigning against the amendment in 2006. She said civil unions, which the amendment banned, are more publicly popular than gay marriages.

Harbaugh said a victory for McConkey will likely lead to new referendums and a reenergized debate about gay marriage throughout Wisconsin. If McConkey is not successful, she said, policies friendly to the LGBT community will gradually enter society.

“Younger people know that discrimination against gays and lesbians is unconscionable, and when it’s our turn and when we become the generation we will repeal it; it just may take some time,” Harbaugh said.