TALLAHASSEE, Fla. (AP) - A libertarian legal group is challenging Florida's law regulating political action committees and similar groups.

The Institute for Justice filed the federal lawsuit Wednesday in Tallahassee on behalf of four Sarasota County residents.

The plaintiffs oppose a land planning amendment to the Florida Constitution that's on the Nov. 4 ballot.

But, the suit says, the law's requirements are so onerous that they've decided against pooling their resources to buy radio ads against Amendment 4.

The Arlington, Va.-based institute contends that violates their First Amendment right to free political speech.

The institute previously won a lawsuit challenging a portion of the same law that has since been revised.