From WNYC in New York, this is NPR's On the Media.

Brooke Gladstone is out this week.

I'm Bob Garfield.

This week, the president gave his long-awaited speech on Afghanistan.

I have determined that it is in our vital national interest to send an additional 30,000 U.S. troops to Afghanistan.

After 18 months, our troops will begin to come home.

And so ends three months of closed-door deliberations, leaks managed and unmanaged,

sniping from Dick Cheney, and rampant speculation from pundits and analysts.

But what about the American public?

Were we swayed by the speech?

Uh, probably not.

Research by political scientists has shown that presidential speeches

seldom, if ever, influence popular opinion,

at least in a long-term, meaningful way.

Most people don't even watch presidential speeches,

and those who do don't necessarily grasp the underlying policy complexities. And anyway,

in the polarized environment of 21st century politics, audiences informed and uninformed are

apt to believe what they wish to believe no matter what the president says.

But if speeches don't really matter, why are the media so obsessed with them?

George Edwards III, a political scientist at Texas A&M, has a theory.

It's fodder for the media. It's what they have in front of them. And so naturally, it becomes

a focus for them to

...