Some gay couples who marry in Illinois might want to consult a lawyer before popping the Champagne cork.

Attorneys are divided on how the state’s “reverse evasive marriage” statute affects the legal status of certain out-of-state couples who tie the knot in Illinois.

The statute bars any couple from marrying in Illinois if they intend to return to their home state to live, and they could not legally marry in their home state. The law declares such marriages null and void.

The Illinois General Assembly did not repeal the evasive marriage statute when it lifted the ban on same-sex marriage.

Richard A. Wilson, a partner at Grund & Leavitt P.C. who handles same-sex family law cases, said the evasive marriage statute leaves the Illinois marriages of same-sex couples from non-recognition states void in both states.

Illinois’ evasive marriage statute therefore defeats the goal of the same-sex marriage law of placing same-sex married couples on the same footing as their opposite-sex counterparts, Wilson said.

“If it’s considered null and void from the beginning, it’s null and void. And there’s nothing you can do about it,” he said.

But John A. Knight of the American Civil Liberties Union and Christopher R. Clark of Lambda Legal Defense & Education Fund Inc. see it differently.

The two are among the lawyers who fought a successful court battle to have Illinois’ ban on same-sex marriage lifted more than three months before the date set by statute.

Knight and Clark noted that the laws in many states say that the marriages of same-sex couples are not “valid or recognized.”

These states use the term “void” for other marriages including bigamous unions, those involving an underage partner or persons with a close blood relationship, the two men said.

“As a result, there is a good argument that Illinois marriages of residents of states that use the ‘valid or recognized’ language are neither ‘void’ in Illinois nor in the couples’ home states,” Knight wrote in an e-mail. “Only if the couple comes from a state that treats marriages of same-sex couples as void should Illinois treat the marriage as void.”

However, he continued, out-of-state couples should consult a lawyer before marrying in Illinois.

“We are working on finding either a judicial or legislative solution to this uncertainty,” he wrote.

Last year, state lawmakers amended the Illinois Marriage and Dissolution of Marriage Act to allow same-sex couples to marry beginning June 1 of this year.

Illinois was the 16th state to legalize same-sex marriage. The District of Columbia also issues marriage licenses to same-sex couples.

Unlike many other new laws, Illinois’ same-sex marriage provision did not take effect Jan. 1 because it was passed during the General Assembly’s veto session. A larger number of votes than it received would have been required to move up its start date.

But in November, U.S. District Judge Thomas M. Durkin directed Cook County Clerk David Orr to issue a marriage license to a woman suffering from terminal cancer and her partner. Vernita Gray, et al. v. David Orr, No. 13 D 8449.

Two weeks later, U.S. District Judge Sharon Johnson Coleman ruled that the “dire circumstances” facing critically ill people warranted allowing them to marry their same-sex partners without waiting for the June 1 start-up date. Brenda Lee and Lee Edwards, et al. v. David Orr, No. 13 C 8719.

Ruling last month in the same case, Coleman cleared the way for all same-sex couples otherwise eligible to marry to tie the knot in Illinois before June 1.

She held that the state’s bar on marriage between people of the same gender violated the equal protection clause by discrimination against individuals based on their sexual orientation.

Orr, who supports same-sex marriage, was named the defendant in the federal suits in his capacity as clerk.

Courtney Greve, a spokeswoman for Orr, said it is up to out-of-state couples who come to Illinois to marry to determine whether the marriage is legal in their home state.

Orr’s office will determine only if a couple is eligible to marry in Illinois, Greve said.

“The legislature and the federal court agree that denying licenses to same-sex couples can no longer be justified,” she said. “The clerk’s office will continue to issue marriage licenses to any couple who meets the basic requirements.”

Wilson is worried that many of the same-sex couples who come to Illinois from out of state to marry face legal jeopardy.

Illinois courts, he said, have continuing jurisdiction over same-sex marriages contracted in the state even if the parties never live here.

This could cause problems for couples who return to their non-recognition states, Wilson said.

For example, he said, the federal government now recognizes same-sex marriages for tax purposes if the marriages are valid where they were celebrated.

So a same-sex couple who weds in a state that recognizes same-sex marriage and that does not have an evasive marriage statute, Wilson said, may file a joint federal tax return even if they live in a non-recognition state.

However, he said, a same-sex couple living in a non-recognition state who married in Illinois could be violating federal law if they file a joint return because Illinois considers their marriage to be void.

A same-sex couple from a non-recognition state who marry in Illinois also could run into legal difficulties if they later split up, Wilson said.

He said one party could halt divorce proceedings or prevent the equitable distribution of assets acquired during the marriage on the ground that the marriage was void from the beginning.

Wilson said many couples could face these types of problems because Illinois — like most states — does not have residency requirements for marriage.

And Illinois’ location makes it a prime destination for same-sex weddings between out-of-state residents, he said.

“We’re right on the corner of three non-recognition states,” he said.

Indiana has a statute, and Wisconsin and Michigan have state constitutional amendments specifically banning same-sex marriage.

Andrew Martin Mayer Koppelman, a law and political science professor at Northwestern University, predicted the evasive marriage statute will affect the city’s bottom line as well as some same-sex couples’ marital status.

“That probably will cost Chicago some tourism revenue,” he wrote in an e-mail.

However, Koppelman continued, same-sex couples who have not yet wed should have little trouble finding a site for their nuptials.

“Most states don’t have these laws, so these couples have lots of other places to go,” he wrote.

In addition to Illinois, states that have evasive marriage laws are Wisconsin, Louisiana and Vermont.

Wilson said members of the Illinois bar should warn lesbians and gay men who plan to wed of the legal minefield he believes they face.

“Lawyers have a duty to advise people of this,” he said. “It could well seriously impair the hopes of a lot of people.”

Illinois Rep. Greg Harris, a Democrat from Chicago who sponsored the same-sex marriage law in the House, said he intends to talk to legal experts about the impact of the evasive marriage statute.

Currently, Harris said, people gain and lose rights as they move from state to state.

“Until we get a coherent, universally accepted regime for recognition of marriage equality throughout all 50 states, we’re going to run into all kinds of problems,” he said.