The U.S. and Iran are staking out increasingly entrenched and opposing positions over Tehran’s nuclear program, threatening the prospects of a vital foreign-policy initiative of President Barack Obama . The U.S. Treasury Department on Thursday announced new enforcement actions against companies with links to Iran for allegedly evading American sanctions against the country and aiding its nuclear and missile programs. The enforcement comes as both Democrat and Republican lawmakers exert pressure on the Obama administration to toughen its posture against Iran ahead of Feb. 18 talks aimed at ending any nuclear-arms threat from Tehran. Some congressional members and U.S. allies are concerned that an initial easing of sanctions against Iran has begun to open the floodgates of investment to the country before it has made any major concessions. But Thursday’s move strained Washington’s diplomatic engagement with Tehran, which said that the move violated terms of the negotiating process both […]