WASHINGTON -- President Barack Obama on Monday proposed a quick $50 billion boost in federal spending to rebuild roads, railways and runways -- a move he said will create jobs and which Democrats hope will improve their election prospects in November.

Obama rolled out the Labor Day proposal at a speech to a friendly union audience in Milwaukee, the launch of a week-long push on the economy and jobs that will include an Ohio speech pushing tax breaks for business and a White House news conference on Friday.

It all comes as the country pivots to a fall campaign for control of Congress in which Democrats are expected to take a pounding. Independent analysts predict the Democrats could lose control of the House of Representatives, and perhaps the Senate, thanks largely to anger and anxiety about the economy. Unemployment this week ticked up to 9.6 percent.

Obama vowed that his new proposal would create jobs immediately. "All of this will not only create jobs now, but will make our economy run better over the long haul," he said.

Obama's proposal would rebuild 150,000 miles of roads and highways, construct and maintain 4,000 miles of railway, rebuild or repair 150 miles of airport runways and upgrade the nation's air-traffic control system.

It also would boost spending for buses and to modernize the Amtrak fleet of railroad cars.

The plan would authorize spending and transportation policies for six years.

Aides did not say how much the overall plan would cost. They said only that the $50 billion spent at the outset would be a "significant share" of the total price.

They said the spending would be offset over 10 years, in part by raising taxes on the oil and gas industry.