The Republican National Committee filed a complaint on Friday to force federal election officials to allow the party to raise unlimited money from individuals, opening a new front in its legal battle on campaign regulation.

The lawsuit, filed in United States District Court for the District of Columbia by the national committee along with the Republican organization of Louisiana, would open a loophole in the 12-year-old law banning parties from raising unlimited checks from wealthy donors, unions and corporations, known as “soft money.”

If successful, the suit would allow party officials to solicit large contributions from their party’s biggest givers to pay for independent advertising campaigns on behalf of party candidates, similar to those waged in recent elections by “super PACs” and other outside groups. The suit does not challenge the ban on contributions from corporations and unions, though it leaves open the possibility of doing so later.

Republican officials say the change would restore much-needed balance to the political playing field. National and state party institutions have been limited to raising relatively small checks — so-called hard money — in the years since the McCain-Feingold campaign law took effect. But super PACs, unleashed by the Supreme Court’s Citizens United decision in 2010, have risen to spend hundreds of millions of dollars each election cycle.