A number of states are quietly considering merging their healthcare exchanges under ObamaCare amid big questions about their cost and viability. Many of the 13 state-run ObamaCare exchanges are worried about how they’ll survive once federal dollars supporting them run dry next year. Others are contemplating creating multi-state exchanges as a contingency plan for a looming Supreme Court ruling expected next month that could prevent people from getting subsidies to buy ObamaCare on the federal exchange. The idea is still only in the infancy stage. It’s unclear whether a California-Oregon or New York-Connecticut health exchange is on the horizon. But...