WASHINGTON – Advocates and skeptics of the Iran nuclear deal are plotting their final moves for support as Congress prepares to return from August recess next week to a consequential vote on the accord.US President Barack Obama has nearly secured the votes necessary in the Senate to preserve the deal, which is to face a resolution of disapproval vote by September 17. To do so, he needs the support of only one-third of senators or an equivalent number in the House of Representatives.That would allow him to sustain a veto of the resolution, should it pass. But his new goal, according to aides, is not only to pick up three additional senators, but to prevent the vote entirely by securing a total of 41 Senate Democrats in support of the deal.Doing so allows the Democrats to filibuster, effectively preventing the vote from occurring. As of Monday, 31 senators had declared support for the accord.Only two Democrats have joined a united Republican caucus, comprising 54 members in opposition. But those numbers are expected to change this week as undecided Democrats prepare to declare their intentions.Senator Chris Coons (D-Delaware) is to deliver a speech on his decision Tuesday, and Senator Ben Cardin (D-Maryland) planned to meet with his constituents on the same day, as he considers his own vote.Cardin’s meeting on Tuesday morning, at Johns Hopkins University, is to precede another Maryland community gathering: One held by the American Israel Public Affairs Committee, or AIPAC, just outside of Baltimore that evening.AIPAC is hoping to secure Cardin, Coons and several other key Democrats on the fence who have expressed several concerns with the accord. Those include Senators Richard Blumenthal of Connecticut, Bob Casey Jr. of Pennsylvania, Ron Wyden of Oregon, Michael Bennet of Colorado and Heidi Heitkamp of North Dakota.The speechifying looks to continue on Wednesday when US Secretary of State John Kerry, who personally negotiated the deal, plans to respond to some of their concerns in an address in Philadelphia. His predecessor and front-runner for the Democratic presidential nomination, Hillary Rodham Clinton, is to deliver her first lengthy address on the deal a week later.Clinton’s speech coincides with a rally against the deal on Capitol Hill held by Tea Party Patriots – a conservative political group – expected to draw thousands, including front-runner for the Republican presidential nomination Donald Trump as well as fellow candidate, Senator Ted Cruz of Texas.The day before that September 9 rally, former vice president Dick Cheney is delivering a speech on the deal at the American Enterprise Institute, a conservative think tank.Congress returns from recess on September 8.