You've seen the images dozens, perhaps hundreds, of times. The self-amused face of Hitler, addressing an outdoor rally. The row upon row of jack-booted soldiers, marching in industrial lockstep. The piles of books being put to the flames.

And though the images are as familiar to you as home movies, they take on a new immediacy in Ken Burns' latest PBS documentary, The War. Burns has chosen to tell the story of World War II not through the eyes of the leaders and decision-makers, but from the perspective of soldiers and their families back home. Interviewees tell their small part of the story, with all the doubts, confusions, and uncertainties of individuals, unlike the historians who have weighed libraries of evidence or journalists who have interviewed multiple sources.

Sixty-six years later we are certain about so many things. We know the threat Hitler posed to the Jews, and all humanity, in the 1930s. We understand the folly of isolationists who insisted America had no stake in the foreign battles. We know the shame of those who did too little to halt the Nazi menace. And yet Burns' series, especially in its early episodes, is a reminder of what wasn't known at the time, either because it couldn't be known, or because those who did know weren't telling, or because those who should have known failed to find out.

The unmistakable message at Monday's rally at the UN against Iran's president is that we can't allow uncertainty to keep us from facing the inevitable. The speakers, and those waving signs calling Ahmadinejad the new Hitler, are certain that the lessons of the past are guideposts to the future. Even if they can't be certain that Iran is the next Reich, they are convinced that we can't afford to get it wrong. "All options are on the table," said Sen. Robert Menendez, the New Jersey Democrat. "I never thought a man would arise who we could compare to Adolf Hitler," said Rep. Jerrold Nadler, the New York Democrat.

Neither is exactly calling for a military action, but analogies have their own power. If Ahmadinejad is the new Hitler, what alternative is there to a military strike? What politician wants to be remembered as his era's Chamberlain?

So the anti-Iran rhetoric gets stronger and stronger, and inevitably begins to build over the possibility of military response to snuff the country's nuclear ambitions.

The rally-goers sent a strong message that Jewish Americans and their friends in the Christian world will not stand by while another dictator gathers the means to annihilate Jews. Message heard.

But analogies aren't reliable guides to action, and hysteria is not a policy. Beyond the slogans, there needs to be a more robust debate within the Jewish community about America's options toward Iran. And this isn't about what "they" will think — that Jews and Israel are pushing America into another war. "They" think that anyway. If we want to be taken seriously as activists and advocates, we must get past the slogans and anti-Ahmadinejad cartoons. We must ask serious questions.

What do we know about Ahmadinejad, beyond his statements denying the Holocaust and his dreams of a world without Israel? Analogy would tell us that is all we need to know, but, again, analogy is no substitute for thinking. How much power does he hold in Iran? How much is his populist bombast meant as a distraction from Iran's financial woes? How united are Iranians behind their leaders?

How credible is the Iranian nuclear threat? Should we trust Mohamed ElBaradei, head of the International Atomic Energy Agency, when he says, "Iran does not constitute a certain and immediate threat for the international community"? Or is he playing down Iran's own boasts that it has 3,000 centrifuges for uranium enrichment already in place?

What are the alternatives to military action? Is the only alternative to bombing Iran "appeasement"? Can tighter UN sanctions on Iran work and are they even possible without the cooperation of the reluctant Russians and Chinese? Pundits talk of a "third option," a diplomatic full-court press somewhere between military action and appeasement. Are they being heard in White House?

And if bombing is the only option, are we prepared for the consequences? Can an administration that did not anticipate the insurgency in Iraq assure us that a military strike on Iran wouldn't inspire a terrorist surge throughout Iraq, Syria, and Jordan? What would be the impact on the economy, and on global stability, if Iran and its supporters were to disrupt the energy market by withholding oil and gas? Does America's strapped military have the capability to handle a sustained confrontation?

These are serious questions, and they are being asked by serious people. Even Daniel Pipes, a reliable hawk when it comes to radical Islam, has written about a "third, more palatable option" to bombing or appeasement. Pipes' scenario relies on mobilizing opposition elements in Iran. It depends on "consistent external pressure on the Iranian body politic" from Europeans, Russians, Chinese, and Mideast states acting in sync with the United States. Pipes knows that such international cooperation is not materializing but suggests that the consequences of bombing or appeasement are too great for us not to exhaust the diplomatic possibilities.

Rallies are great things. They mobilize adults, educate young people, and provide politicians here and abroad with a measure of citizens' concerns. And yet the Iran question is too dire to be played out only in the streets. There are important questions about Iran to be asked and answered. America's Jewish leaders owe a measured, serious discussion to the millions of American Jews in whose name they presumably act.