I'm not sure if there's a proper term for this, but I'm looking for a word or phrase that describes the act of taking advantage of a (presumably negative) situation (that may have been staged) in order to justify another action that might not have been as well received if the incident hadn't happened.
For example,
A government stages a terrorist attack against its own nation so that it can declare war against another nation. The citizens are less outraged and more supportive because it's seen as an act of retaliation instead of an act of aggression.
It seems like describing it as a form of propaganda would be fine, but I'm not sure if there's a more specific term that could be used.