"Seventeen states—all but two headed by Republicans—are suing to block Obama’s effort to regulate carbon emissions. GOP governors led the drive to resume offshore drilling after Obama suspended it following last year’s BP spill in the Gulf of Mexico. From the other direction, the president did his part to heighten tensions by suing Arizona over its immigration law and conspicuously siding with public-employee unions in their struggle with GOP governors (the most notable so far led by Wisconsin’s Scott Walker) over collective-bargaining rights."