RIO DE JANEIRO — As U.S. warplanes pounded faraway Libya, President Barack Obama praised Brazil's transition from dictatorship to democracy as a model for the Arab world where decades of stability enforced by strongmen is giving way to an uncertain but potentially brighter future. --snip-- He said those protesters showed how a popular revolt could produce a thriving democracy. And without specifically mentioning the military action he authorized just a day ago in Libya, the president drew a connection to the events there and throughout the Middle East.....