Balancing conflicting interests within a coalition is tough. Among Democrats, tension persists, for example, between unions and the party's supporters in global finance. Democrats have tried to mediate that conflict by, among other things, supporting free-trade agreements that include provisions specifically favored by labor. The party faces a similar struggle between labor and environmentalists, who have wildly divergent opinions about the benefits of, say, pipeline construction. Likewise, Democrats occasionally stick it to their wealthy supporters, raising their taxes. Other times, they retreat, as when they abandoned President Barack Obama's plan to tax 529 education plans.