For more than six decades, the fight against nuclear proliferation has been a central concern of the left. From J. Robert Oppenheimer in the 1940s to Helen Caldicott in the 1980s, proclaiming "No Nukes" has been an easy way in for the "Yes We Can" crowd. The 2008 Democratic platform, envisioning "a world without nuclear weapons," reflected Barack Obama’s deep yearnings, and the left-leaning academic milieu from which he came.

Given that, it is surprising—and dismaying—that the fight to block Iran’s rush toward nuclear weapons has not stirred progressive passions. Such things are hard to quantify, but it has not been a popular issue on the left. The level of activism pales in comparison to1980s’ standards. There has been no 700,000-person demonstration in Central Park, no prime time apocalyptic television movie like the ABC 1983 blockbuster "The Day After," no push like the one from the International Physicians for the Prevention of Nuclear War, which won the 1985 Nobel Peace Prize.

Here we seem to have a case of nuke-washing (or radioactive cleansing, as it were), with two possible explanations. First, just as Palestinians who target Israelis are often called "militants" when their al-Qaeda comrades who target Americas or other innocents are "terrorists," threatening Israel does not generate the same outrage as threatening other countries. The Non-Aligned Movement farce that played out in Teheran last week, not only undercut the Obama administration’s salutary push to isolate and sanction Iran, but it made countries like India complicit in Iranian war-mongering when their delegates did not object to the rhetorical targeting of Israel. Similarly, on campus and in other progressive centers, Israeli checkpoints for security trigger many more protests than Iranian plans for weapons of mass destruction.

My late grandfather would have sighed and said, "Jewish life is cheap." But it's a culture of blaming Israel, demonizing Zionism, and romanticizing Palestinians that gives Israel’s enemies a free moral pass in too many quarters. Israel’s controversial policies regarding the Palestinians have created a popular construct that delegitimizes the Jewish state (and the entire Zionist project) well beyond the confines of the Holy Land.

The concept of "pinkwashing," for example, had to be developed to overcome progressive cognitive dissonance. How could a country that has been so demonized, whose very essence has been deemed corrupt and evil, be so much more enlightened than its neighbors on that core value of the left, equal rights for the LGBT community? Simple: turn that genuine expression of Israeli democracy and human rights into a propaganda ploy by the supposedly sinister, all-power Israeli Hasbara manipulators and lobbyists.

The second explanation reflects a broader historical phenomenon. Since the 1960s, the culture of Western self-flagellation has created an outrage gap, exaggerating any Western, liberal democratic imperfections while excusing many serious Third World crimes. We saw this in the 1970s, when the UN was silent for years regarding the genocide in Cambodia, occupying its time instead branding Zionism as racism and bashing the U.S. as colonialist. We saw this in the 1980s, when the left-wing "no nuke" protests in Europe and the U.S. focused much more on American proliferation than Soviet expansionism and weaponry. This culture of self-blame purports to be anti-racist, but actually reflects liberal condescension and its own imperialist arrogance. Rather than holding every country to the same moral standard, all too often dictatorial enemies of the United States get a free pass—especially those from the Third World.

While the myopic left long excused the sins of others, there was a more muscular, less hypocritical progressive tradition in the 1940s, 1950s and 1960s that vigorously fought dictators and international outlaws. As our own Peter Beinart wrote in his 2006 book, The Good Fight, "antitotalitarianism" once sat "at the heart of the liberal project." It was the Henry Wallace—George McGovern—Michael Moore counter-tradition that "preferred inaction to the tragic reality that America must shed its moral innocence to act meaningfully in the world."

Barack Obama arrived in the Oval Office in 2009, frequently sounding like he was a standard bearer of that purist, pacifist, appeasing counter-tradition. Yet in his steely determination to hunt down al Qaida terrorists with drones, and in his cool-headed approval of the plan to take down Osama Bin Laden, Obama often took the tougher approach, though still with a liberal outlook. Whether he will be equally strong with Iran remains to be seen.

Of course, the "no nukes" crowd will be quick to talk of a nuclear-free Middle East, sweeping Israel into the push against Iranian nuclear proliferation. Here, too, the nuke-washers will reflect a double standard. Israel's weilds its presumed decades-old nuclear power quietly, as a democracy accountable to its people. The Iranian theoocracy, which threatens the United States, not just Israel, cannot clam the same restraint or accountability to its citizens.

I challenge my colleagues and this generation of the left: stand strong and shout "No Iranian Nukes." Obama committed himself to non-proliferation, and to prevent Iran from acquiring weapons, but he needs the support of progressives, and liberals at home and among the international community.

There could be an immediate peace payoff if the protests take off. Mass protests against Iranian nuclear proliferation might help make sanctions work, might rein in the Iranians, and might make Israel feel less embattled and less compelled to defend itself militarily, even possibly unilaterally against what the Iranians’ own rhetoric has suggested could be an existential threat to the Jewish state and other democracies.