The decision by Moody's Investors Service MCO -0.52% to cut Japan’s sovereign debt rating once again raises awkward questions always lurking just below the surface for the country’s policy makers: Just how long can they defy gravity? When will a debt downgrade exact the punishing toll on Tokyo that such a blow has unleashed on other highly indebted countries, from Europe to emerging Asia and Latin America? The early read: that time hasn’t come yet–though changes in long-time stabilizing fundamentals could be making Japan more vulnerable. Japan has long been the great paradox of the big sovereign borrowers — having ... (full story)