WAYNE, Pa. — Democrat Barack Obama told voters yesterday he would push an aggressive economic agenda as president: cutting taxes for the middle class, raising taxes on the wealthy, pouring money into green energy and requiring employers to set up retirement saving plans for their workers.

Campaigning in Pennsylvania, a key battleground in the fall campaign, Obama said he would take a much more hands-on approach than would Republican John McCain. He again criticized McCain's proposal for a temporary halt in the federal gasoline tax. It would "actually do real harm," Obama said, by reducing revenue for road and bridge construction even as oil companies make record profits.

Obama visited the flooded Midwest later yesterday, stopping in Quincy, Ill., to help fill sandbags.

Speaking to about 200 people in Wayne, a Philadelphia suburb, Obama made no new proposals but emphasized earlier ones in light of rising gas prices, inflation and job losses. They include a $1,000 tax cut for most working households; a new Social Security tax on incomes above $250,000; a "windfall profits" tax on oil companies; a $4,000 annual college tuition credit for those who commit to national or community service programs; and an end to income taxes for elderly people making less than $50,000 a year.

Obama said he could pay for his programs by eliminating the Bush administration's tax cuts for the wealthy, winding down the Iraq war and spending more on alternative energy programs that eventually will save money.

He said employers should be required to set up retirement saving plans for workers even if they contribute no money to them. Workers would automatically be enrolled unless they choose to opt out, he said. That way, he said, "most people will save more."

He also proposed spending $150 billion over 10 years toward a "green energy sector." It would require greater fuel efficiency in cars and devote more money to solar, wind, and biodiesel energy.

In Quincy, Obama helped volunteers fill sandbags being trucked to reinforce levees on both sides of the Mississippi River, less than a mile away. Authorities expect the river at Quincy to reach a near-record level of 32 feet by Wednesday. Severe flooding already has hit Cedar Rapids, Iowa, northwest of Quincy.

"Since I've been involved in public office we've not seen this kind of devastation," Obama said as he used a shovel to fill bags being held by local resident Dylan Muldoon, 10. He vowed to push the federal and state governments to provide needed aid to the stricken areas.

Obama and McCain are battling over Iowa, which gave Obama a crucial Democratic caucus win in January. Obama had planned to campaign in Cedar Falls last Wednesday, but the flooding canceled that.

Aides said Obama chose to avoid Iowa this weekend because he did not want to draw government resources away from the efforts to help flood victims and to prevent flooding in areas still above water.