WASHINGTON (AP) -- The Obama administration is proposing to cut the corporate tax rate from 35 percent to 28 percent, and to seek an even lower effective rate for manufacturers, a senior administration official says.

In turn, corporations would have to give up dozens of loopholes and subsidies that they now enjoy. Corporations with overseas operations would also face a minimum tax on their foreign earnings.

Treasury Secretary Timothy Geithner on Wednesday was to detail aspects of President Barack Obama’s proposed overhaul of the corporate tax system, a plan Obama broadly outlined in his State of the Union speech last month.

Chances of accomplishing such change in the tax system are slim in a year dominated mostly with presidential and congressional elections. But for Obama, the proposal is part of a larger tax plan that is central to his re-election strategy.

The corporate tax plan dovetails with Obama’s call for raising taxes on millionaires and maintaining current rates on individuals making $200,000 or less.

The 35 percent nominal corporate tax rate is the highest in the world after Japan. But deductions, credits and exemptions allow many corporations to pay taxes at a much lower rate.

Under the framework proposed by the administration, the rate cuts, closed loopholes and the minimum tax on overseas earning would result in no increase to the deficit.

That means that many businesses that slip through loopholes or enjoy subsidies and pay an effective tax rate that is substantially less than the 35 percent corporate tax could end up paying more under Obama’s plan. Others, however, would pay less while some would simply benefit from a more simplified system.

The official said the Obama plan aims to help U.S. businesses, especially manufacturers who face strong international competition. Obama’s plan would lower the effective rate for manufacturers to 25 percent while emphasizing development of clean energy systems. The administration official spoke on condition of anonymity to describe what the administration will do.

The New York Times first reported details of the plan in its online edition early Wednesday.

Many members of both parties have said they favor overhauling the nation’s individual and corporate tax systems, which they complain have rates that are too high and are riddled with too many deductions.

The corporate tax debate has made its way into the presidential contest. Former Massachusetts Gov. Mitt Romney has called for a 25 percent rate, former House Speaker Newt Gingrich would cut the corporate tax rate to 12.5 percent, and former Sen. Rick Santorum would exempt domestic manufacturers from the corporate tax and halve the top rate for other businesses.

While Obama has been promoting various aspects of his economic agenda in personal appearances and speeches, the decision to leave the corporate tax plan to the Treasury Department to unveil signaled its lower priority.

What’s more, the administration’s framework leaves much for Congress to decide _ a deliberate move by the administration to encourage negotiations but which also doesn’t subject the plan to detailed scrutiny.

Obama’s plan is not as ambitious as a House Republican proposal that would lower the corporate rate to 25 percent.

Still, Obama has said corporate tax rates are too high and he has proposed eliminating tax breaks for American companies that move jobs and profits overseas. He also has proposed giving tax breaks to U.S. manufacturers, to firms that return jobs to this country and to companies that relocate to some communities that have lost big employers.

Geithner told a House committee last week that the administration wants to create more incentives for corporations to invest in the United States.

"We want to bring down the rate, and we think we can, to a level that’s closer to the average of that of our major competitors," Geithner told the House Ways and Means Committee.

White House economic adviser Gene Sperling has advocated a minimum tax on global profits. Currently many corporations do not invest overseas profits in the United States to avoid the 35 percent tax rate.