From the beginning, I knew the public reaction to my decisions would be colored by whether there was another attack. If none happened, whatever I did would probably look like an overreaction. If we were attacked again, people would demand to know why I hadn't done more. That is the nature of the presidency. Perceptions are shaped by the clarity of hindsight. In the moment of decision, you don't have that advantage. On 9/11, I vowed that I would do what it took to protect America, within the Constitution and laws of our nation. History can debate the decisions I made, the policies I chose, and the tools I left behind. But there can be no debate about one fact: After the nightmare of September 11, America went seven and a half years without another successful terrorist attack on our soil. If I had to summarize my most meaningful accomplishment as president in one sentence, that would be it.