Republican Senators are developing a strategy to override an expected presidential veto of a resolution of disapproval of the Iran nuclear agreement. And while they will be working on getting 13 Democratic Senators to go against President Obama and support killing the deal, one Democrat is aboslutely key to their plan.

New York Senator Chuck Schumer, a strong friend of Israel, is genuinely torn over supporting his party leader or voting against a deal he knows is bad for Israel. If Republicans can convince him to support the disapproval resolution, that will pretty much be the ball game. There are 7 or 8 other Democratic Senators, strong friends of Israel all, who would be likely to follow Schumer in opposing the agreement.

Meanwhile, the GOP is crafting a PR strategy to get maximum effect from exposing a divided Democratic party unsure of supporting a bad deal.

The Hill:

Only one Senate Democrat, Sen. Bob Menendez (N.J.), announced opposition to the deal on Tuesday.

But Republicans believe they will win the public relations battle on the deal, which largely unites the GOP and threatens to divide the Democratic Party.

Some Senate Republicans are thinking about moving a motion of approval of the deal, believing it would put Democrats in a tough spot ahead of next year’s elections. Such a move in the upper chamber could lead to less than half of the Senate backing the president, allowing for more favorable headlines for the GOP. The House, however, is more likely to pass a resolution of disapproval.

A third option is to move legislation sponsored by Menendez and Sen. Mark Kirk (R-Ill.) placing new sanctions on Iran, which the Banking Committee passed earlier this year and has Democratic support.

“All options are on the table,” said a Republican member of the Senate Foreign Relations panel who requested anonymity. “I wouldn’t take anything off.”

Republicans will likely use the Iran votes as ammunition on the campaign trail in 2016. But Democrats have the bully pulpit, and the Obama administration has initiated a huge campaign to sway the public.

New York Sen. Charles Schumer, the third-ranking member of the Senate Democratic leadership, is emerging as a critical vote.

Senate Republicans need to hold their ranks and persuade 13 Democrats to vote with them to override President Obama’s threatened veto of a resolution of disapproval.

“If Schumer comes out and says, ‘I looked at the bill and studied its details and think it’s a good deal and will stop Iran from getting weapons,’ there will be zero hope of overriding an Obama veto,” said Noah Pollak, executive director of the Emergency Committee for Israel, which funded a six-figure Web campaign targeting Schumer earlier this year.

“If Schumer says this doesn’t do it, it lifts the arms embargo and doesn’t have anytime, anywhere inspections, then we have a fight on our hands. He’s a linchpin or a bellwether,” he added.

Both sides are confident they can win, given the circumstances. Realistically, Republicans have a tougher hill to climb given Obama's position as leader of the party. and his ability to appeal to Democrats to support one of his singular achievements. But this deal is so bad, all bets are off. WIth pro-Israeli groups set to mount a massive lobbying campaign against the agreement, anything at this point can happen.