The president answered a question about it during his Twitter town hall this week, but you can really read his answer two ways -- either as ruling the option out, or as simply saying he'd hate to have to get to the point where he had to use it.
Writing in the Western Daily Press, Mr Cameron said: "I know that a great deal of work has been done to try and alleviate the situation but it is not acceptable for people to have to live like this almost four weeks later - and I am not ruling out any option to get this problem sorted out.
It is time for the Obama administration to reverse course and begin ruling options in, rather than ruling options out.
The administration is not ruling out any option, an administration official said.
"By remaining discreet," Mr. Prosper said, "you are not ruling out the option to be more public later.
However, Hammond said the UK was not ruling out the option of strikes against Isis in Syria.
That approach now focuses the two countries' efforts on preventing Iran from obtaining nuclear weapons, while also ruling out the option of a retreat to containing and deterring a nuclear-armed Iran.
Officials at the Defence Department are privately saying the same thing.And so, for the moment at least, the Clinton team is united in ruling out the option of ground troops.
On Wednesday, the Senate approved a bill banning new energy exploration in land designated as national monuments, ruling out an option that administration officials said should not necessarily be excluded from efforts to increase domestic energy production.
Danny Boyle's 2012 ceremony did well with its sprouting factory chimneys and newly forged Olympic rings, unfairly ruling out that option for Glasgow, which owes far more of its character to the industrial revolution than London does.
