A controversial plan that would have allowed small businesses to offer cut-rate health insurance has failed. The Health Insurance Marketplace Modernization and Affordability Act would have allowed businesses to band together across state lines and purchase insurance directly from trade associations or business groups.

The Enzi bill--named after author Michael Enzi, a Republican senator from Wyoming--stalled in the U.S. Senate over a provision that would have allowed association health plans to sidestep dozens of state guidelines that mandate coverage for treatment for a variety of conditions including diabetes, infertility, mental illness, alcoholism, and Lyme disease. Mandates over cancer screening, including mammography, would also have been voided, which provoked the greatest outcry.

The dispute pitted a majority of state attorneys general and the American Cancer Society against business groups, which supported the low-cost plans. Enzi has vowed to push on. "The voice of people without insurance keeps getting louder," he said in a statement. "My colleagues will have to listen."