Two weeks after key parts of the Defense of Marriage Act were struck down by the U.S. Supreme Court, the American Civil Liberties Union announced it would pursue a lawsuit against Pennsylvania, North Carolina, and Virginia, challenging their bans on same-sex marriage.

"The ACLU has been a leader on this front since bringing our first marriage lawsuit in 1970 and we've been deeply involved in opening marriage up to same-sex couples in each of the 13 states plus the District of Columbia that now have marriage equality," the ACLU says on its website. "Our goal is at least 20 states with the freedom to marry by the end of 2016, and we are working towards that goal using four different advocacy tools."

Despite the high court's ruling, the legality of same-sex marriage remains an issue states have the authority to decide.

1) Virigina

The Virgina chapter of the ACLU, in partnership with LGBT advocacy group Lambda Legal, announced it will sue the state of Virginia over its ban on same-sex marriage.

The state amended its constitution to ban same-sex marriage in 2006 after a 57 to 43 percent statewide vote. However, Claire Gastanga, the executive director of the ACLU-Virginia chapter, said the organization will challenge the ban because it violates the equal protection clause in the U.S. Constitution.

"There is no rational reason for denying these loving couples the freedom to marry and every reason to grant them the same recognition by civil authorities that opposite-sex couples have,” Gastanaga said.

Kenneth T. Cuccillini, Attorney General and Republican gubernatorial candidate for Virginia, expressed his commitment to uphold Virginia's law, stating he would "continue to defend the will of the people of Virginia, an overwhelming majority of whom voted to protect the definition of traditional marriage under Virginia’s Constitution.”

2. North Carolina

In addition to a similar suit over the constitutionality of North Carolina's same-sex marriage ban, the ACLU of North Carolina seeks to amend a federal lawsuit for the second parent adoption rights of same-sex couples. In December 2010, the state passed a statute restricting the ability for one partner to adopt the others biological or adoptive children to heterosexual couples.

As the ACLU states on its website:

Some of the protections that come with a second parent adoption include: ensuring that all children in the family are covered if one partner lacks health insurance, ensuring that families will stay together and children will not be torn from the only home they've known if something should happen to the biological parent, ensuring that either parent will be allowed to make medical decisions or be able to be by their child’s bedside if one their children is hospitalized

The suit is comprised of six same-sex couples, including Marice and Chantelle Fisher-Borne, for whom the case is named. Each woman is the biological mother of one of their two children, but ran into legal issues when legal paperwork for their daughter was demanded.

“The law in North Carolina does not recognize the life we have built together or allow us to share legal responsibility for the children we have raised together." Chantelle Fisher-Borne said. "We want to be married for many of the same reasons anyone else does – to do what’s best for our family, especially our children, and have our commitment to each other recognized by the law."

3. Pennsylvania

There are 23 couples fighting to have their out-of-state same-sex marriage recognized by Pennsylvania.

The case's lead plaintiffs are Deb and Susan Whitewood. a couple, who have been together for 29 years. Despite a civil union in Vermont, Pennsylvania does not honor their relationship, and the couple argues the lack of legal regard for their union is discrimination by the state. Reggie Shuford, executive director of the ACLU of Pennsylvania, supported the ACLU's decision to sue the state.

"As the cradle of American liberty, it is shameful that Pennsylvania denies some families the dignity and respect that can only come with marriage," Shuford said. "It's wrong that the state where these couples live, work, and raise families treats them as second-class couples."