Seth Perlman, Associated Press
FILE - In this April 16, 2012 file photo, a 2011 1040 tax form along with other income tax forms are seen at the entrance of the Illinois Department of Revenue in Springfield, Ill.

The following editorial appeared recently in the Los Angeles Times:

Politicians on both sides of the partisan divide want to simplify the federal tax code by pruning the thicket of loopholes. In fact, President Obama and his presumptive Republican opponent Mitt Romney, have both promised to seek tax simplification. A new study, however, shows that if simplification is coupled with a deep cut in rates, as Romney has proposed, lower- and middle-income Americans would have to pay more in taxes just to keep the same amount of revenue flowing into the Treasury. That's because the necessary reduction in exemptions, deductions and credits would more than offset the savings from the lower rates.

There are compelling reasons to simplify the tax code, such as reducing tax-avoidance trickery. The complexity, however, stems in part from widely enjoyed tax breaks. And despite broad support for simplification, the parties are split over whether proceeds should reduce the deficit or lower tax rates.

Romney has proposed to reduce rates by 20 percent, eliminate the alternative minimum tax, end the estate tax and give lower- and middle-income families a larger tax break for investment income. He's also said, however, that his tax plan would not increase the deficit. So to offset the cost of the tax cuts, he has proposed to curtail unspecified tax breaks for individuals.

The Tax Policy Center study estimates that individual tax exemptions, deductions and credits would have to be reduced by as much as two-thirds to cover the $360 billion annual cost of Romney's tax cuts. Because those breaks are significantly more valuable to low- and middle-income families than Romney's proposed tax cuts would be, the authors conclude, the Romney plan's benefits would accrue mainly to the wealthy, and its costs to everybody else.

The Romney campaign and the Tax Foundation argue that the new study underestimates the economic growth that would be spurred by Romney's plan to lower individual and corporate tax rates and cut federal spending. But even the Tax Foundation acknowledged that Romney's approach would make the tax code less progressive, shifting some of the burden from the wealthy onto low- and middle-income taxpayers. If nothing else, the Tax Policy Center study should make lawmakers more conscious of the potential winners and losers in tax simplification as they debate changes in the tax code over the coming months. And in the meantime, Romney should reveal more details of his tax plan so that voters of more modest means can see what they stand to lose.