It is possible that advances in the future of neuroscience may lead to new technologies for "hard" and/or "quasi-hard" mind control (see  for an explanation of these terms). I wish to point out that this has great import for philosophy.
Here are some quotes (or perhaps misquotes) showing that it has long been regarded as true that one's will cannot be subverted:
"The commander of the forces of a large state may be carried off, but the will of even a common man cannot be taken from him." -- Confucius
"Do not regard as valuable anything that can be taken away." -- Seneca
"That which does not kill us makes us stronger" -- Frederic Nietzsche
The quote from Confucius becomes clearly false with the existence of hard mind control. The quote from Seneca presumably wishes for the reader to regard as valuable various inner resources such as willpower and memory -- but if hard mind control exists, then its import is instead that nothing is valuable. Nietzsche's quote becomes false if we assume that "strength" is the ability to use one's willpower; if willpower itself can subjected to an external attack, then there exists a process by which one's strength can be made less.
It is my belief that a good deal of philosophy is built upon this sort of assumption, and hence will have to be rethought if reasonably comprehensive, hard mind control becomes available.