What’s the reason for this gulf between popular and congressional opinion? In part, it’s because hawks are more mobilized. An ultra-hard line against Iran has been near the top of the agenda of AIPAC—and its associated political action committee—for two decades now. AIPAC distributes its money to both parties. But in recent years it has been joined by GOP billionaires, like Sheldon Adelson, who have been liberated by the Supreme Court to spend vast sums for the purposes of shifting the Israel and Iran debates further right. Tom Cotton alone got more than $2 million from these Iran hawks in his 2014 Senate run.

Doves often decry this, but the bigger question is: Why can’t they compete? MoveOn.org and a variety of other progressive groups recently sent a letter warning Democratic senators not to kill the Iran deal. And in the absence of Israeli-Palestinian negotiations, Iran has moved near the top of J Street’s agenda. Still, the discrepancy between the political pressure being exerted by hawks and doves is stunning. A GOP senator who supported the Iran deal would become a virtual pariah in his party and quite likely face a primary challenge—despite the fact that a plurality of rank-and-file Republicans support the deal. In the Democratic Party, by contrast, where public support for last Thursday’s agreement is overwhelming, Charles Schumer can vocally endorse the Corker-Menendez bill, which might well scuttle the Iran deal, without at all imperiling his rise to Senate Majority Leader.

More than a decade after the invasion of Iraq, despite the disasters that American military intervention has brought, there is still a culture of impunity for Democratic politicians who defy their party’s voters on questions of war and peace.