ROME - Matteo Renzi, staging a political comeback less than five months after resigning as Italy's prime minister, easily regained the leadership of the ruling Democratic Party (PD) on Sunday with an overwhelming victory in a primary election among party supporters.According to partial results, Renzi had about 72 percent of the vote, held in makeshift polling booths around the country. About 2 million party members voted in the primary. Justice Minister Andrea Orlando had 19 percent while Michele Emiliano, the governor of the southern Puglia region, had about 9 percent.Both of his opponents, as well as Prime Minister Paolo Gentiloni, called to congratulate him, and Renzi gave a long victory speech at party headquarters."Forward together," Renzi said to applause.Renzi, 42, resigned as prime minister in December after a crushing defeat in a referendum over constitutional reforms aimed at streamlining lawmaking. He was replaced by Gentiloni, his foreign minister, but he quickly began planning a comeback.