An invasion of armies can be resisted, but not an idea whose time has come.

Nothing else in the world... not all the armies... is so powerful as an idea whose time has come.

There is one thing stronger than all the armies in the world, and that is an idea whose time as come.

All the forces in the world are not so powerful as an idea whose time has come.

More powerful than the mighty armies is an idea whose time has come.

The ideal and the beautiful are identical; the ideal corresponds to the idea, and beauty to form; hence idea and substance are cognate.