The state of Alabama enacted a statute that imposed a tax on premiums earned by insurance companies. The statute imposed a 1 percent tax on domestic insurance companies (i.e., insurance companies that were incorporated in Alabama and had their principal office in the state). The statute imposed a 4 percent tax on the premiums earned by out-of-state insurance companies that sold insurance in Alabama. Out-of-state insurance companies could reduce the premium tax by 1 percent by investing at least 10 percent of their assets in Alabama. Domestic insurance companies did not have to invest any of their assets in Alabama. Metropolitan Life Insurance Company, an out-of-state insurance company, sued the state of Alabama, alleging that the Alabama statute violated the Equal Protection Clause of the U.S. Constitution. Who wins and why?