(CBS) Earlier this month, Social Security turned 70.

Some Americans, including President Bush, think the retirement program is ripe for overhaul.

But, after a six-month-long campaign, Mr. Bush has made little headway in convincing Americans that a radical change of Social Security is a good idea.

As CBS News Correspondent Dan Rather reports, the group most responsible for opposing the President's social security reform plan is the AARP.

Those letters used to stand for the “American Association of Retired Persons.” And, even though the AARP still goes by that name, its leaders say the group now represents not just retirees, but Americans 50 and older.

And that's a lot of people. The AARP has more than 35 million members, making it the largest organization in the United States after the Catholic Church. It is a three-quarters-of-a-billion-dollar-a-year business. And, it's one of the most powerful lobbying groups in Washington.

The AARP has become a remarkable marketing and political machine.

Rather wanted to see how that machine works, so he started by going to the AARP convention in Las Vegas. It's not the kind of event where elderly people play shuffleboard.

It was more than a sound-and-light show for the 25,000 AARP members who showed up at the convention. There was entertainment and inspiration.

Bill Novelli, the AARP's leader, focused on-stage on what he sees as a key message: "We're here to celebrate the power to make it better. … At AARP, we do have the power to make it better. …When we talk about power, we're talking about you."

Smokey Robinson was on stage, too.

If you're wondering how he became an attraction for the senior set, it's because the group began shedding its older image when its leaders realized that baby boomers, people born in the decade or so after World War II, are the demographic future.

So AARP dropped its name and kept just the initials. And, it dropped the membership age to 50.

Today, half of AARP's members are between 50 and 65, years away from retirement and Social Security. That means they don't always see eye to eye with older members, making it difficult for AARP to represent both generations.

"How can you do that?" Rather asks Novelli. "It will strike a lot of people as trying to be all things to all people."

"It struck me that way, too, in the beginning," Novelli says. "… It is possible, I think, to speak to all generations."

What's the most difficult part of that?

"Well, the boomers are different in many ways. You know, they've got an attitude. They've always been catered to. …But then … they need what every other generation needs. They need retirement security. They need good health. They need health care."

AARP still pays attention to its older members.