Barack Obama secures vital vote to keep Iran nuclear deal

US president Barack Obama has secured a landmark foreign policy victory amid opposition from Republicans and Israel. The win was achieved when Democratic senator Barbara Mikulski became the 34th vote to back the Iran nuclear deal.

Her backing gives supporters the margin they need to uphold an expected Obama veto of a congressional resolution of disapproval Republicans hoped to pass later this month.

And it spells failure for opponents of the international agreement who sought to foil it by turning Congress against it.