It didn’t take long for Sen. Chuck Schumer’s gutsy decision to buck Obama on Iran to stir up intraparty fervor. The Jewish lawmaker, who hopes to succeed Harry Reid as Senate Democrat leader, did himself no favors by announcing Thursday he “will vote yes on a motion of disapproval.” Just like colleague Robert Melendez and other audacious Democrats who’ve dared to challenge Obama’s agenda, Schumer’s dissent is risky. And wouldn’t you know it: Shortly after Thursday’s announcement, Team Obama launched an unofficial campaign to ruin Schumer’s leadership bid. Ex-speechwriter Jon Favreau tweeted, “Schumer, who said it was a mistake to pass Obamacare, now comes out again the Iran Deal. This is our next Senate leader?” Former advisor Dan Pfeiffer was more subtle, but added, “Schumer siding with the GOP against Obama, Clinton, and most Democrats will make it hard for him to lead the Dems in ‘16.” Meanwhile, former campaign spokesman Ben LaBolt slammed Schumer’s “[t]imely endorsement of the foreign policy of the GOP candidates,” while White House Press Secretary Josh Earnest called the decision “disappointing” and advised Democrats to “consider the voting record of those who want to lead the caucus.” As for the man who negotiated the deal, John Kerry opined, “I obviously profoundly disagree with the judgement made.” As of Monday morning, a CREDO Action petition already had accrued the signatures of more than 160,000 Americans. “There’s no excuse for any Democrat to oppose the deal — least of all Senator Schumer, who is in line to take over leadership of the Senate Democrats once Senator Harry Reid retires,” the petition reads. Yet how many can say they’ve taken time to thoughtfully consider Schumer’s surprisingly well-reasoned critique? There’s plenty to dislike about Schumer, but on the Iran issue, he’s right. The question is whether he’s willing to stand on principle and sacrifice his chances of taking Reid’s baton to defend it. Only time will tell.