Dictators love embargoes. Just look at North Korea - if you can gain entry. The secretive Stalinist state hosts few foreigners, either as visitors or residents. When I visited Pyongyang in 1995 to report on a Hong Kong-based investor's bid to operate there, the negotiations were plagued by a shortage of English speakers with enough knowledge of financial matters to translate properly.
North Korea's language deficit is symptomatic of the isolation that is key to the power of Kim Jong Il, its leader. Though embargoes deprived Pyongyang of modern weaponry - its non-conventional arms, which may soon include nuclear weapons, are another matter - they have also shut North Koreans off from the world, along with the toxic ideas and technologies that could undermine Mr Kim's authority. The Brussels-based International Crisis Group recently called on the international community to assist Pyongyang by training North Koreans in business and finance. But Pyongyang is unlikely to expose its people to ideas it cannot control. Far from subverting the regime, sanctions have provided North Korea's leaders the antiseptic curtain they need to cut their people off from the world.
Now consider Syria, currently preparing for the ruling Ba'ath party congress on June 6. Analysts say there are signs that Bashar al-Assad, Syria's president, will unveil political reforms consistent with George W. Bush's campaign to democratise the Middle East. Nonetheless, the White House is proceeding with plans that would empower hardliners in Damascus in the same way they have strengthened those in Pyongyang: shrouding Syria in a comprehensive trade embargo.
The Bush administration's intensifying pressure on Damascus is part of a move to uproot the Assad regime through external pressure. Little matter that Damascus has been for the last 16 months or so managing a tentative political and economic opening.
Foreign-controlled, private banks have been operating in Syria for a year and Syrians have for the first time been permitted to hold foreign exchange. Dissidents are increasingly vocal and several groups have launched independent non-governmental organisations, fertile ground for civic institutions that could offer compelling opposition to the regime. And while activists differ on how best to challenge Mr Assad, their message to Washington is broadly similar: back off.
Most Syrians dread the Syrian Accountability Act, passed overwhelmingly by the US Congress two years ago in response to Syrian support of Lebanon's Hizbollah and other anti-Israel groups. If fully enforced - some provisions were implemented last May - the act would limit the country's interaction with the outside world and allow the regime, in the manner of Pyongyang, to control what comes in and what goes out. This would undermine activists, who need to project their message, and would also create a siege mentality that Mr Assad and his lieutenants could manipulate to stifle dissent.
Resonant in Damascus but lost on Washington is how the United Nations-led embargo on Iraq and the accompanying smuggling trade so enriched Saddam Hussein he could buy the loyalty of tribal and religious leaders. They dramatically thinned Iraq's population of diplomats, businessmen and aid workers, to say nothing of spies, which allowed Mr Hussein to commit his most egregious acts free of international scrutiny. They also eviscerated Iraq's once-robust middle class, historically an antechamber for reform and revolution. While Syrians might applaud the White House for standing up to Arab autocracy, they fear the collapse of the political air-pocket Mr Bush helped create unless he rigorously engages the Middle East and its problems, rather than simply isolating and neglecting them.
The Ba'ath party congress will reveal much about the nature and motives of both Syrian and US leaders. If Mr Assad unfurls an agenda for substantial reform - expectations have been raised for the release of jailed dissidents and a green light for a multi-party political system - it will prove he is strong enough to do what is right and smart enough to call Mr Bush's bluff.
A commitment to real change would be enough for the European Union, led by France, to rally behind Damascus, leaving the White House with a choice: abandon the sanctions threat along with ambitions for another Middle East intervention, or stay faithful to unilateral instincts and defy international currents - including the majority of Syrian opinion.