Russia has been supportive of the Syrian regime, but if it wanted to assist the United States, it could pull its military advisers out of Syria and stop its alleged supplying of arms to the regime.
Russia could also tell Syrian President Bashar al-Assad to hand over power to an interim administration.
Such Russian support is unlikely, and the most that the Obama administration could expect is Russia expressing uncertainty about whether the Assad regime is the best to govern Syria, as Russia did a year ago.
So what kind of a coalition could we be talking about?
When all is said and done, any U.S.-led coalition against Syria could be one that offers more moral than military support.
That is still important, especially when the nations act outside the aegis of the United Nations Security Council.
"A coalition is political in nature, but the United States would do the heavy lifting militarily," Tabler said.