The big GOP tax-cut bill now under Senate consideration would provide a better deal for middle-income taxpayers than the tax cuts House Republicans passed last week, analysts say. But not even conservative tax experts claim that either measure qualifies as a middle-class tax bill.

"There is a middle-class tax cut in the [Senate] bill," said J.D. Foster, executive director of the Tax Foundation, a conservative-leaning group. "The tax cut that goes to the middle class is not the dominant element of the bill, however."

Like its House counterpart, the Senate bill is a mix of broad tax relief and more narrowly targeted provisions, many of which will effectively be available only to wealthier taxpayers, such as estate-tax modifications and the lifting of limits on certain individual retirement accounts (IRAs) that are unavailable to those making a lot more than $100,000 a year.

But a chief feature of the Senate bill, which is expected to pass by the end of this week, is a cut in the lowest tax bracket from 15 percent to 14 percent. That allowed the bill's author, Senate Finance Committee Chairman William V. Roth Jr. (R-Del.) to portray the measure as a "broad-based tax cut plan that will benefit nearly every working American."

The argument over whether either GOP bill offers significant help for middle-class taxpayers goes to the heart of party differences over tax cuts. Democrats have hammered Republican tax proposals all year by saying they are heavily tilted toward the rich. Republicans have consistently defended their tax proposals on the grounds that tax cuts should go to high-income taxpayers, because they're the ones who pay most taxes.

But the Democratic attacks have clearly stung. Roth took pains to draw a more centrist bill than the House measure. His focus on the lowest tax bracket contrasted with the House bill's 10 percent across-the-board cut in tax rates, which would help low-income taxpayers but would also cut rates all the way up into the income stratosphere, giving even the richest taxpayers a 10 percent rate cut. The House bill also would repeal the estate tax--paid by only the top 2 percent of estates, generally those worth more than $650,000--and reduce the capital gains tax rate.

Overall, the House bill's focus on upper-income tax breaks tilts its benefits heavily toward the best-off taxpayers, according to Treasury Department figures, which are not disputed by the bill's Republican sponsors. The middle 60 percent of taxpayers--a rough definition of the nation's middle class--would get only about 20 percent of the value of the House bill's tax breaks, while the top fifth of all taxpayers would take home about 80 percent of the cuts.

The Senate bill, by contrast, would devote nearly 33 percent of its tax breaks to middle-class taxpayers, more than half again as much as in the House bill. That amount is also nearly identical to the 34 percent of the total federal tax burden that Treasury figures show is now paid by that same middle 60 percent of taxpayers, roughly those families earning from about $16,000 to $82,000 a year.

On the other hand, the Senate bill still targets 67 percent of its tax breaks to the top fifth of taxpayers. That's fine with most Republicans, in part because it nearly matches the 65 percent of total federal taxes paid by that same top fifth of taxpayers, or those who make more than about $82,000 a year. But critics say it shows that the bill is no boon for the middle-income taxpayers who need relief more than wealthier taxpayers.

"One shouldn't go too far overboard in saying [the Senate bill] is better for the middle class," said Iris Lav, deputy director of the Center on Budget and Policy Priorities, a liberal-leaning think tank. "When you put down something like the House bill first, anything's going to look better for the middle class."

Lav and other analysts note that the Senate bill contains several tax breaks aimed almost exclusively at upper-income taxpayers, and they say that even its chief middle-class tax break is a better deal for upper-income taxpayers than for the middle class it appears designed to help.

When he unveiled his bill in a radio address July 9, Roth said it would give a typical middle-income family of four a tax break of $450 a year. Lav said that is true--but only for those at the very top of the 15 percent bracket, which means families with a gross annual income of about $61,000.

For families with less income, the break would be smaller: $188, for example, for a family with total annual income of $37,000, which Lav said would put them exactly in the middle of the income range.

While most families in the 15 percent bracket would not get the $450 tax break Roth mentioned, all taxpayers in higher tax brackets would get it, since the first increment of their income is taxed at 15 percent (before the balance is taxed at higher rates).

The Senate bill also includes a variety of changes to rules governing IRAs and other savings vehicles that Lav said would effectively be available only to higher-income taxpayers. For example, the bill would lift the income limit on Roth IRAs, special retirement savings vehicles that are available only to single people with incomes of $110,000 or less per year and couples earning $160,000 or less.