WASHINGTON - As vice president, Joe Biden will oversee an Obama administration effort to find ways of building up the ranks of the middle class, that ambiguously defined segment of society with which most Americans identify.

The task force will include four Cabinet members and other presidential advisers, the Obama transition team announced yesterday.

The goal is to recommend proposals to ensure the middle class is "no longer being left behind," Biden said. The proposals could include executive orders and legislative plans.

Biden said the measure of economic success in an Obama administration would be whether the middle class was growing.

In an interview broadcast yesterday on ABC's "This Week," Biden took care to define his role as vice president as going beyond a particular task. He said that when he discussed the job with Barack Obama during the campaign, he told Obama he didn't "want to be the guy that goes out and has a specific assignment." Rather, he wanted to have a voice in every matter of importance.

"I said I want a commitment from you that in every important decision you'll make, every critical decision, economic and political as well as foreign policy, I'll get to be in the room," Biden said.

He said that Obama agreed and has adhered to that commitment.

Biden also covered several other topics:

_ The loan agreement for automakers will require sacrifices from all segments of the industry. He said that although organized labor had not brought the carmakers to the brink of collapse, unions are "going to have to make some additional sacrifices, and they know it and they understand it."

_ The economic-aid plan being readied by the Obama team will focus on creation of a strong energy grid, will pay for thousands of new jobs focusing on making buildings and homes more energy-efficient and will help health-care providers invest in electronic record keeping for patients. "The end result, though, the money we're spending, we're going to get back three- and four-fold."

_ He said that the military prison at Guantanamo Bay, Cuba, should close, and that the U.S.'s reputation abroad has suffered as a result of the Bush administration's policies on surveillance and detainees. "To quote from a previous national security report put out by the intelligence community, we have created, not dissuaded, more terrorists as a consequence of this policy," Biden said.

_ He said that it's up to the Justice Department to determine if charges should be filed against any member of the Bush administration for prisoner abuse that occurred at Abu Ghraib or Guantanamo. *