[edit]
to clarify, the reason I made this comment is to note a case where this strategy has been used in history, as mentioned by the parent post. Not to compare Obama/Bush to Hitler.
She mostly approaches the issues from an economical perspective, mainly focusing on inhumane economic policies that both Thatcher and Reagan implemented, but the gist is similar.
Therefore it is not surprising that shocking events lead to controversial laws. Shocking events arguably lead to most laws; it's hard to get something done unless something shocking gets the public's (and members of congress') attention and causes a reaction.
Of course, people in power are aware of this phenomenon and plan their tactics to take advantage of it. I remember reading that many provisions of the Patriot Act were written long before 9/11 and its authors had been awaiting an opportunity. Or as the Obama administration said early in its tenure (IIRC), 'never waste a crisis'.