U.S. Rep. Jason Altmire and challenger Melissa Hart argued yesterday over Social Security, a potent issue in the senior-rich 4th Congressional District.

Accepting the endorsement of a national seniors group, Mr. Altmire, a Democrat who ousted the Republican Ms. Hart two years ago, accused his predecessor of wanting to privatize Social Security and said this month's meltdown in the stock market proved that she would have put the retirements of millions at risk.

"In 2000, maybe that seemed like a good idea. We had just had eight straight years of economic growth," Mr. Altmire said. "The problem is when you do the individual retirement accounts, what you do is you pull $1 trillion to $2 trillion out of the current trust fund and put it into individual accounts."

Accepting the endorsement of the National Committee to Preserve Social Security and Medicare during a morning news conference at the Ross Municipal Building, Mr. Altmire said Ms. Hart eight years ago pushed for investment account diversions from Social Security by individual workers and dismissed the possibility of a market failure.

"Then state Sen. Melissa Hart was asked, 'Well, what if we have a situation like 1929? Does that give you pause when thinking about putting Social Security trust fund money into the stock market?' " Mr. Altmire told the group yesterday. "She said, and I quote, 'We're more sophisticated today than we were in 1929. That could never happen again.' "

In fact, Ms. Hart said "we're a bit more sophisticated than in 1929" and did not suggest a market crash could not happen again.

Yesterday, Ms. Hart dismissed the National Committee to Preserve Social Security as overtly political and defended her stand on including private market investments as a share of Social Security. She said her proposals would have kept intact the benefits of older workers currently invested in the system.

"What I actually wanted to do during the Social Security program was I wanted to preserve it in its present form ... where nothing would change as far as their paying in or receiving benefits," she said.

"But we would make it optional for young people, especially young people; it would allow them the option of staying in the current system or having their dollars put in an account with their name on it so they would realize some kind of Social Security later."

The pair will have an opportunity to thrash the issue out at a scheduled public debate Oct. 23 at the Penn State Beaver campus.