Four of the six seats on the Federal Election Commission are vacant, with nominations caught up in partisan gridlock in the US Senate. The FEC can still disclose data on elections, but without a quorum, it can't issue regulations and binding opinions or file lawsuits.

"Everyone is running around Iowa and New Hampshire, and no one noticed that the FEC closed for business last week," says Anthony Corrado, a campaign-finance expert at Colby College in Waterville, Maine.