In general terms, the Administration will be pressing Republicans to shift the tax cuts away from higher-income taxpayers.

"Most higher-income taxpayers have enough expenses to itemize their deductions," the study said.

Investment income would not be taxed at all under the individual tax, which by itself benefits predominantly higher-income taxpayers.

However, this deduction would phase out for higher-income taxpayers, reducing to zero for couples earning over $250,000.

"These are working people we are trying to help," Senator Lincoln said, adding, "The higher-income taxpayers get enormous benefits from the tax code."

He revised his plan, however, when Republicans charged that higher-income taxpayers would pay too much.

One concern is that higher-income taxpayers are already reaping a growing share of the nation's economic wealth.

Further clouding the issue of progressivity is that far more deductions and tax credits are available to higher-income taxpayers.

The alternative tax is intended to prevent higher-income taxpayers from taking advantage of too many deductions.

The package includes a long list of tax changes that would largely affect businesses and higher-income taxpayers.