A runner's stride is not perfectly efficient.

[Former chief executives] come away thinking that America needs a strong, functioning presidency to succeed, and they become very protective of that office. Democrats and Republicans alike are willing to put aside their own party's self-interest to preserve the presidency. That's been true over the decades.

Time is valuable; people are busy.

Death will never be pretty - its sights and smells too close and crude. And it will never come under our control: it gallops where we tiptoe, rips up our routines, burns our very breath with its heat and sting.

In many parts of the world, more people have access to a mobile device than to a toilet or running water...

If you want to humble an empire it makes sense to maim its cathedrals. They are symbols of its faith, and when they crumple and burn, it tells us we are not so powerful and we can't be safe. The Twin Towers of the World Trade Center, planted at the base of Manhattan island with the Statue of Liberty as their sentry, and the Pentagon, a squat, concrete fort on the banks of the Potomac, are the sanctuaries of money and power that our enemies may imagine define us. But that assumes our faith rests on what we can buy and build, and that has never been America's true God.

On a normal day, we value heroism because it is uncommon. On Sept. 11, we valued heroism because it was everywhere.