Social Security Shortchange?

Up before dawn every day, Marti Flint of Ellsworth, Maine isn't scared of hard work.

She's a teacher's aide, a bus driver and a mother of two.

As CBS News Correspondent Mika Brzezinski reports, what frightens her is the future and going broke when she finally retires.

"My biggest fear is that I am going to be one of those little old ladies who cannot afford tuna and will have to buy cat food," she says.

By the time she's 65, Marti will have paid into social security for 50 years, but "I will only see 40 percent of it," Flint says.

How could that be? In an effort to keep Social Security afloat, Congress passed a law 20 years ago that barred highly-paid citizens, who already have pensions, from receiving full Social Security benefits.

But it's not just highly-paid workers who lose out. In Maine and 14 other states, public servants - teachers, firefighters, police - pay into a state retirement plan, instead of Social Security. Because of that little-known federal law, those workers cannot receive their full Social Security benefits from their private sector work. Like their better paid counterparts, low paid public workers can't "double dip."

So Marti, a teacher's aide for 6 years, a job that gives her a small state pension, will get less than half of her social security - which she's paid into for 35 years. Instead of the projected $629 a month, she'll only get $252 a month when she retires.

"We paid it to them. We loaned it to them with the understanding that we would get our money back," says retired teacher Sue Shaw, who started a national grassroots campaign to repeal the federal law, calling it plain and simple.

"Robbery. They are stealing our money," she says.

Edith Fierst served on the Social Security advisory council under President Clinton. She says the law doesn't need fixing.

"It would cost so many millions and millions of dollars to do this for everybody and why would you want to favor these people," she says.

"All I did wrong was I came to work at a school," Marti tells Brzezinski.

Marti Flint says she just wants what she paid for and feels shortchanged in life.

"In a nutshell, I'll be OK if I don't live too long ... when you are countin' your nickels and dimes, you have to think that way," she says.

Marti can count on one thing: unlike millions of workers, she knows just how little money is coming her way when she retires.