MIAMI -

A coalition of black and Hispanic civil rights groups and pastors is challenging the grounds of a lawsuit that seeks to overturn Florida's constitutional ban on same-sex marriage.

Their attorney said Friday that the lawsuit "infringes on Florida voters' rights to amend their state constitution and their access to the political process."

"The political question doctrine removes from the courts certain issues of public policy that are just incapable of judicial determination, and we argue same-sex marriage is one such issue," attorney Alexander Alfano said.

The ban passed in November 2008 with 62 percent of the vote. It defines marriage as "the legal union of only one man and one woman as husband and wife."

The groups include the Florida Democratic League and PULSE. They filed court papers saying a judge should dismiss the lawsuit.

In January, six gay couples sued in Miami-Dade County court, saying Florida's gay marriage ban violates the U.S. Constitution's guarantees of equal protection and due process.