The White House is close to securing the votes it needs in Congress to keep the nuclear agreement with Iran on track despite fierce opposition from Republicans and a multimillion-dollar advertising campaign against the deal. A steady trickle of Democrats has come out in favour of the deal in recent days, giving the White House almost enough votes to prevent Congress from blocking the historic agreement, which was reached in Vienna last month. Some Democratic Senate aides believe there could even be enough support in the party to filibuster a resolution against the deal, which would mean the president would not need to actually wield a veto in order to secure his second term foreign policy priority.