The leader of the Federal Election Commission, the agency charged with regulating the way political money is raised and spent, says she has largely given up hope of reining in abuses in the 2016 presidential campaign. The likelihood of the laws being enforced is slim," Ann M. Ravel, the chairwoman, said in an interview. "People think the F.E.C. is dysfunctional. It's worse than dysfunctional." Her unusually frank assessment reflects a worsening stalemate among the agency's six commissioners. They are perpetually locked in 3-to-3 ties along party lines on key votes because of a fundamental disagreement over the mandate of the commission, which was created 40 years ago in response to the political corruption of Watergate. The F.E.C.'s paralysis comes at a particularly critical time because of the sea change brought about by the Supreme Court's decision in 2010 in the Citizens United case, which freed corporations and unions to spend unlimited funds in support of political candidates. Experts predict that the 2016 race could produce a record fund-raising haul of as much as $10 billion, with the growth fueled by well-financed outside groups. On their own, the conservative billionaires Charles G. and David H. Koch have promised to spend $889 million through their political network.