I’ve yet to be convinced that anyone knows what the end game on the Iran nuclear deal will be, but its future in the Senate is going to be touch and go. The GOP seems to be in lockstep against it … mostly. But that doesn’t mean that a vote to shoot the deal down is a sure thing. Even if it were, the President gets to weigh in with his veto pen and then you need Democrats if you want to get past the Oval Office. And we’re not just talking about a few Democrats either.

In terms of the minority party opposition, it does exist. Joe Lieberman (now safely out of the fray and into retirement) seems to be the voice of those still in office who are a bit more shy about speaking up. He’s been doing the media tour lately and putting the pressure on Chuck Schumer (D – NY) to take a stand for Israel.

Lieberman, the Senate’s first Orthodox Jew, blasted the agreement with Iran on “The Cats Roundtable” with host John Catsimatidis on New York’s AM 970.

He said the deal could be effectively blocked with the help of Sen. Chuck Schumer (D-N.Y.).

“I think it opens the way for a lot of other Democrats to oppose it as well,” Lieberman said of his longtime colleague, who is also Jewish. “Chuck is the key.”

Schumer, who is likely to become the Senate’s next top Democrat, faces a major dilemma over the nuclear deal. He is both a key ally to both Israel and the White House, facing pressure from both sides on the deal.

Schumer is in a ticklish position here, not only by virtue of being being Jewish himself, but having been a long time friend and supporter of both Israel in general and Bibi Netanyahu in particular. He’s been a bit of a thorn in Barack Obama’s side on the Middle East since the beginning of his term. As early as 2010, Chuck was speaking to the press out of school and calling for the President’s counter-productive Israel policy to stop. As recently as this spring, when rumors were making the rounds about Obama strong arming Israel and hinting about less support for them in the U.N. the Weekly Standard cornered Schumer and couldn’t get more than a “No Comment” from him.

The point is that Schumer hasn’t been afraid to buck the Democrat system to stand up for Israel and Bibi’s feelings about this deal are clear to say the least. But now Schumer is on the brink of something big. Every rumor mill source in DC has it that Schumer is in line to replace Harry Reid as Minority Leader (and Majority if they manage to take the Senate back) and that means playing ball. It’s been obvious for years that Chuck has had his eye on the big chair and he loves nothing more than showing up on every cable news show that will have him.

So what will Chuck do? If he stands up forcefully against the Iran deal he will provide cover for a lot of other nervous Democrats to follow him over the cliff. But he’ll also be setting his bridges on fire with both the White House and the rest of the party leadership. He’s unbeatable in New York, so there’s no danger of losing his seat entirely, but he’s probably wondering whether opposing the deal will sink his chances at the Leader position. It looks like a choice between principle and personal gain, and only Schumer knows which he will pick.