Foreign Minister Avigdor Lieberman recently suggested a not-so-novel approach to the problem of Iran's nuclear ambitions. He wants to apply what he calls the Cuban model, in which "the United States alone can do everything in order to stop this program."

Lieberman went on to suggest, "If the United States adopts the legislation and the entire Cuban model toward Iran, without awaiting understandings and consensus within the [UN] Security Council framework, this would be enough to strangle and bring down the Iranian regime."

To anyone who follows the case of Cuba, a few contradictions immediately pop up. For starters, Lieberman seems to think the United States embargo has "already proven its efficacy." One hopes that Israel has a higher standard of success than the United States has had with Cuba. The efficacy Lieberman lauds is an absurd standoff that has impeded important progress for the U.S. in its dealings with allies in Latin America and beyond.

But for Israel's foreign minister, achieving success is easy: The U.S. embargo should simply "shun foreign firms that continue to do business with Iran." This sort of extraterritorial component was added to America's Cuban embargo in 1996 with the passage of the Helms-Burton Act. But, perhaps unbeknownst to Lieberman, it has been dutifully waived every six months since, at the behest of our allies.

And speaking of allies, Lieberman may also be surprised to know that one of the first countries that would suffer the consequences of such a "shunning" is Israel, which is a leading investor in Cuban agriculture. According to the U.S. Department of Agriculture, Israeli capital has driven a reinvigoration of Cuba's citrus sector, to such an extent that a joint venture now produces one-third of the island's total citrus output. If Israel can make the Middle Eastern desert bloom, imagine what it's been able to achieve in the fertile soil of this Caribbean island.

Fortunately, few policy-makers - even among Cuban embargo supporters - are interested in repeating the 50-year embargo experiment with that nation in the Middle East. In fact, irony of ironies, the example of Israel is instructive on this point: When president George W. Bush was doing his best to isolate Syria, Israel was conducting talks with it, in the hope of reaching a peace agreement.

Last month President Obama named career diplomat Robert Ford as the first U.S. ambassador to Damascus since 2005, bringing an abject policy failure to an end. At least it didn't take the U.S. 50 years to learn its lesson.

To be sure, its new engagement with Syria has not achieved America's goals: The previous U.S. ambassador there, Margaret Scobey, was withdrawn after former Lebanese prime minister Rafik Hariri was assassinated in an operation presumed to have been set in motion in Damascus. Today, blame for that act has still not been officially assigned. And the current Israeli government made clear, by naming Lieberman foreign minister, that talks with Syria about peace, or anything else, are off the table.

Still, the current consensus in the United States is that there are concrete advantages to having an ambassador in Damascus. Ambassador Ford is now engaged in high-level contacts with the Syrian government that will give Washington fresh insight into what's really happening in the country. And the fact that U.S. policy is no longer all stick and no carrot can only help America to become better informed about all the issues at play in the region, from Turkey to Afghanistan and beyond. This may even help Israel.

Lieberman doesn't see this; he thinks diplomacy is for weaklings. And if he thinks the United States can simply use sanctions to bring down the Iranian regime, just wait until he sees the kind of diplomacy that such sanctions will require in the 21st century.

Cuba is a relatively easy case: a small, poor island located a short distance from the United States. But the Castro brothers are still firmly in charge and they only benefit the harder the United States squeezes them. They use the embargo as a trump card, an explanation for all the shortages their people face. And times have changed: The world economy is more integrated and includes more significant trade powers than when the embargo was initiated. Cuba has friends, such as Brazil and China, with money to invest, and they tend to be important partners for America, too. So, Cuba's doing pretty well, in spite of the embargo.

Iran cultivates relationships with these same rising world trade powers, and has a lot more to offer those partners than Cuba does. Iran is a populous, resource-rich country. Complicating matters for the United States further, Iran is nestled in a complex, far-off region. And, like it or not, America needs it: Iran is as essential to the withdrawal of U.S. troops from Iraq and Afghanistan as China was to our withdrawal from Vietnam.

In fact, if the United States hopes to influence Iran's direction, it should consider the path taken in engaging China: Long-term, consistent and strategic engagement there have yielded a productive, interdependent - and yes, complicated and often confrontational - relationship. If the United States hasn't been able to smother little Cuba, what makes anyone think the blunt instrument of sanctions will even be possible, much less effective, with Iran? Sanctions or genuine engagement: Either way, diplomacy is required. Why not employ it in a way that can yield a good outcome for both sides, rather than one that will lead to misery for Iranians and yet another, extremely costly struggle for the United States?

Lieberman's invocation of Cuba is instructive, though not in the way he probably hoped: It points out the futility of putting U.S. policy on the sanctions-first, ask-questions-later basis. Good thing no one takes him seriously. Right?