US interests sometimes clash with its support for democracy in the Middle East, Secretary of State Hillary Clinton acknowledged Monday, but she said democratic freedoms were the best guarantee of stability in the long run. In a speech on Washington's response to the Arab Spring that toppled several US allies, Clinton implicitly faulted the military council that succeeded former Egyptian President Hosni Mubarak for moving too slowly on elections. She also acknowledged that the United States sometimes deals differently with pro-democracy movements, saying no two situations are the same and that diverging US interests sometimes force it to adopt varying stances. Clinton used her her speech to the National Democratic Institute to address questions such as why the United States built a military coalition to force Libyan dictator Muammar Gaddafi from power while it has been more cautious in Syria. The US justification for intervention in Libya -- to protect civilians -- would also appear valid in Syria, where activists say that Syrian President Bashar Al-Assad's forces have killed hundreds of civilians seeking an end to his rule. “Sometimes, as in Libya, we can bring dozens of countries together to protect civilians and help people liberate their country without a single American life lost,” she said. “In other cases, to achieve that same goal, we would have to act alone, at a much greater cost, with far greater risks and perhaps even with troops on the ground,” she added. “Our choices also reflect other interests in the region with a real impact on Americans' lives -- including our fight against al Qaeda; defense of our allies; and a secure supply of energy,” she said. In the careful language of diplomacy, Clinton had tough words for the military council that took power in Egypt after forcing long-time US ally Mubarak from office following mass protests against his three-decade authoritarian rule. “If, over time, the most powerful political force in Egypt remains a roomful of unelected officials, they will have planted the seeds for future unrest. Egyptians will have missed a historic opportunity. And so will we.” Clinton said the United States must be prepared to work with democratically elected leaders that do not agree with it, including Islamist parties such as that which just won Tunisia's first free election last month.