The author of a mandatory GMO labeling bill will not support a labeling proposal by USDA Secretary Tom Vilsack. Senator Jeff Merkley, a Democrat from Oregon, says he opposes Vilsack’s approach to GMO labeling. Merkley introduced a mandatory labeling bill just a day after the Senate Agriculture Committee approved a voluntary measure by Kansas Republican Senator Pat Roberts, Chairman of the Senate Agriculture Committee. Vilsack’s proposal, known as mandatory disclosure, would use smart labels and 1-800 numbers for consumers to find more information. Merkley responded by saying Americans do not want “to stand in a grocery store and make phone calls to companies,” according to the Hagstrom Report. All three proposals would ban state labeling laws, such as the Vermont law that takes effect in July. The Senate was expected to vote on the voluntary labeling proposal by Roberts in the coming week. Vilsack has said the federal system has to be mandatory to get the 60 votes to pass the Senate.