whether one can; whether it is possible

No one can deny the fact.

To those who seek peace and security. We support you. And to all those who have wondered if America's beacon still burns as bright, tonight we proved once more that the true strength of our nation comes not from the might of our arms or the scale of our wealth, but from the enduring power of our ideals: democracy, liberty, opportunity and unyielding hope.

Could you tell me the way to the station?

Should we play?

I can neither confirm nor deny that.