Top U.S. and NATO military leaders are exploring the possible political and military fallout in Syria if Western powers decide to remove Syrian President Bashar al-Assad by military force.
Those scenarios were one of many issues covered during Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey's meeting with alliance leaders in late April, he said during a Tuesday speech in Washington.
Despite those ongoing discussions, Dempsey made clear there was nothing the U.S. or NATO could do to guarantee any political outcome in a post-Assad Syria, if military action is taken.
"There are certain things we cannot do," he said during Tuesday's speech.
That said, the four-star general was adamant that last month's discussions in Brussels did not include any military planning for possible action against the Assad regime.
But the perceived failure of a U.N.-backed peace plan to quell Assad's violent crackdown against anti-government rebels in Syria has left NATO with little choice but to begin assessing other options, including military action.
Assad's government agreed to a cease-fire plan proffered by U.N.-Arab League envoy Kofi Annan and backed by the U.N. Security Council in April.
The plan called for Assad to pull his troops back and stop attacking rebel strongholds in Homs and elsewhere in the country. Critics claim the plan lets Assad retain the presidency even if the violence stops.
But reports claiming Syrian troops continue to carry out attacks on major population centers in the country have prompted some on Capitol Hill to argue the Annan plan has failed.
Those lawmakers, led by Sens. John McCain (R-Ariz.) and Joe Lieberman (I-Conn.), argue that military action is now the only option left to depose Assad.
Turkey's recent threat to invoke Article 5 of the NATO charter only ratcheted up that growing pressure for military force in Syria.
Article 5 claims that an attack against one NATO member can be considered an attack on the entire alliance.
Invoking Article 5 could open the door for a NATO-led attack on Assad's forces, similar to the campaign that removed former Libyan dictator Moammar Gadhafi.
Turkish Prime Minister Recep Tayyip Erdoğan said Ankara was considering the move after Assad forces fired into Turkish territory in pursuit of rebels who had fled across the border.