simply use propaganda to change the public's conception of what a "terrorist" is, as well as change the definition according to policy. that policy could either state that there are no terrorists any more, or that there never were terrorists, or that people who were previously terrorists are (surprise!) not any more, or that other people that were not terrorists really are (surprise again!), according to rhetoric and/or policy.
edit: (when I say "you" in the following, I don't mean anyone personally---)
regarding the process of breakdown and redefinition: the first thing a diametrically-opposed administration does is insist, with or without "proof," that most or all information you have learned from the previous administration is false, and that what the new administration says is the truth (many times what the new administration says is not provided along with this--the point is to "break down" your existing constructs and prepare you for the new paradigm); many times the "proof" is not provided through information for you to consider for yourself; instead you or the figures affiliated with the previous information are subjected to personal attacks; you may be attacked regarding your thinking, your emotions, your values, etc. so that you are thrown off balance. It's tough to sift through everything, because what you determine to be the truth is, many times, somewhere in between!