Updated, 4:30 p.m. EDT

WILMINGTON, Del. — Delaware lawmakers introduced a bill Thursday that would legalize same-sex marriage in the state, with plans to have it signed into law by the end of June.

The legislation, which the governor has pledged to sign if passed by lawmakers, was filed a little more than a year after Delaware first began recognizing same-sex civil unions.

Critics of the civil union legislation warned at the time that it was simply a precursor to same-sex marriage in Delaware, which could soon join nine other states that have legalized gay marriage.

Gov. Jack Markell and Attorney General Beau Biden, both Democrats, joined lawmakers and other proponents Thursday to express their support of the bill.

“The department I run, the Department of Justice, is fully committed to correcting an injustice,” Biden said.

The governor said the bill is about the most basic of individual rights, “the pursuit of happiness.”

“It’s time that we do the right thing,” Markell said.

The bill has more than 20 co-sponsors, including one Republican, Rep. Michael Ramone of Newark. It will be heard by the House Administration Committee, chaired by Democratic Majority Leader Valerie Longhurst, on Wednesday.

“This bill is about the most fundamental of American freedoms, the freedom to marry the person you love,” said Lisa Goodman, president of Equality Delaware, a gay rights organization that took the lead in crafting both the civil union and same-sex marriage bills.

As written, the new law would take effect July 1 if it passes the Democrat-controlled legislature.

No new civil unions would be performed after July 1, and couples in civil unions could convert their civil unions to marriages before July 2014 by applying for a marriage license to county clerks of the peace. On July 1, 2014, all remaining civil unions not subject to proceedings for dissolution, annulment or legal separation would automatica lly convert to marriages.

The legislation also states that same-sex unions established in other states will be treated the same as marriages under Delaware law.

In a nod to religious freedom, the bill states that no cleric or minister of a religious denomination would be required to perform or solemnize any marriage that does not conform to his or her religious beliefs.

Still, opposition to legalizing gay marriage in the state remains.

“Marriage serves a purpose and is based on the truth that men and women are complementary, the biological fact that reproduction depends on a man and a woman, and the reality that children need a mother and a father,” Nicole Theis, executive director of the Delaware Family Policy Council, said in a statement. The conservative group is opposed to both same-sex civil unions and gay marriage.

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