Attorneys general in 11 states and the District of Columbia yesterday filed a lawsuit challenging a Department of Labor final rule that changes the definition of “employer” under federal law such that more individuals, including sole proprietors, are eligible to participate in association health plans based on geography or industry. The lawsuit asks the U.S. District Court for the District of Columbia to vacate the rule, claiming it “upends a decades-old understanding of a foundational employee benefits law for the purpose of exempting a significant portion of the health insurance market from the Affordable Care Act’s consumer protections.”