Is the U.S. doomed to a Greek-style meltdown? It seems like just yesterday that we were asking ourselves if the United States was Rome. In light of the financial collapse in the other great cradle of Mediterranean civilization, the New York Times' David Leonhardt poses the inevitable follow-up question: The U.S.'s national debt, Leonhardt notes, is projected to rise to 140 percent of GDP within the next twenty years -- Greece's is 115 percent today. Elsewhere at the Times, Paul Krugman questions the credibility of that long-range projection and argues that the U.S. shouldn't worry: About that eurozone: in a phenomenally awkward bit of timing, Estonia happened to be trying to join it today, and succeeded. Other countries like Poland and Bulgaria, however, are having second thoughts. Greece's current predicament, and the looming crises in Spain, Portugal, and elsewhere, have offered a cautionary tale. The Associated Press looks at the divergent experiences of Hungary and Romania, which are members of the European Union but not the eurozone, and Greece, which is in both: When the IMF bailed out Hungary and Romania in 2009, the countries were able to make the necessary adjustments quickly, if painfully, by letting their currencies fall. Greece, however, can't, and is now looking at far harsher, more drawn-out austerity measures attached to its 110 billion euro bailout.