Sullivan has been associate General Counsel of the Service Employees International Union since 1997. The SEIU is one of the most politically active unions in the country. Its primary endorsement of Obama in February, 2008, helped him build momentum against Hillary Clinton at a key period during the nomination contest. The nomination is likely to cheer organized labor, as well as critics of the FEC, which has suffered from weak leadership over the years. Sullivan is a respected election lawyer, with substantial experience in the field.