U.S. officials have said the deal has the chance to transform and stabilize the Balkans, a region that lags economically behind the rest of Europe and one where Russia battles with the West for influence. But polls indicate that nearly 7 in 10 Greeks oppose the accord, and many accuse Prime Minister Alexis Tsipras of pulling his party away from its populist roots while ramming through a deal that has won him acclaim from abroad.