During Wednesday night's Republican debate, Jeb Bush responded to Donald Trump's criticism of George W. Bush's administration with a non sequitur, citing 9/11—the deadliest-ever attack on United States soil—as evidence that GWB, during whose term the attack took place, had kept America safe:
You know what? As it relates to my brother, there is one thing I know for sure, he kept us safe. I don't know if you remember, Donald. You remember the rubble? You remember the firefighter with his arms around him? He sent a clear signal that the United States would be strong and fight Islamic terrorism and he did keep us safe.
It didn't literally make sense, but Bush was speaking extemporaneously, and maybe what he meant to say is that George W. Bush kept America safe after 9/11. (Some people would dispute that claim as well, of course, but a lot of Republican primary voters would agree with it.) Perhaps, after the debate, Jeb would come up with a more coherent formulation of what he was trying to say.
Again, there are not many people who would argue that George W. Bush should have prevented 9/11. There has been serious criticism of his pre-9/11 counterterrorism strategy, but saying his administration could have made counterterrorism a higher priority is not the same as saying that if they'd done so they would definitely have prevented what was a shocking and largely unimaginable attack. Very few people specifically blame George W. Bush for not keeping the United States safe on 9/11.
But on the other hand, he didn't keep America safe on 9/11. So why does Jeb Bush keep saying he did?