The Obamacare debate is entering a new phase. The problems plaguing the insurance exchanges have raised serious questions about the viability of the president’s health reform effort. The Obama administration and its allies insist that the exchanges will soon be up and running, and that they’ve already been successful. Yet at least some liberals are starting to wonder if the exchange model should be abandoned in favor of a single-payer, Medicare-for-all approach. John Cassidy of the New Yorker, an occasional Obamacare critic from the left, is just one of many liberals who’ve touted the virtues of a single-payer system, and it is easy to imagine future Democratic presidential candidates doing the same. Conservatives, meanwhile, have tended to characterize the failure of the exchanges as a reflection of the limits of government. Patrick Ruffini, a well-regarded conservative strategist, captured the views of many on the right in a short piece titled “How Healthcare.gov Discredits Liberalism.” We’re nowhere near a consensus on whether the kludgy mess that is Obamacare ought to be replaced. But serious questions are being raised across the political spectrum.