When I was young and impressionable, my mother impressed upon me a creed that I thought was universal: Actions speak louder than words. That means I shouldn't go around telling me friends: "I'm a good kayaker." Or "I'm a good father." And I especially don't blankly tout my fathering skills if the record indicates otherwise, if, for example, my kids are routinely expelled from school for drugs, fights, or what have you.
I just do it and let my actions speak for themselves.
Apparently McCain's mother didn't teach him this same creed. McCain's "I'll get Osama Bin Laden, my friends. I know how to get him. I know how to do it" line isn't the first of this variety. He's said the same thing about winning wars, fixing the economy and working across the aisle. He's never offered ANY specifics or even basics about how he would go about accomplishing any of these goals, which I might add, would probably require more mental might than one man can muster.
I'm sure a large percentage of Americans will take McCain at his lofty words and never question how he knows how to fix the economy, catch bin Laden and win wars. They'll never look for proof of his super-human competence in his actions. Probably because if they did, they'd find McCain has no evidence to support his lofty thesis. In fact, they'd probably find evidence to the contrary.

"I'll get Osama Bin Laden, my friends. I know how to get him. I know how to do it." —John McCain

"The economy is in crisis and I know how to fix it." —John McCain

"I know how to win wars, my friends." —John McCain