One of the most telling moments in the recent presidential debate among the Democrats came when Senator Clinton was pressed on the “Mother of All Tax Reforms” recently offered by her New York colleague, Rep. Charles Rangel. Mrs. Clinton said she wouldn’t use the Rangel plan as her campaign platform. The conventional interpretation was that she didn’t want to be locked in to supporting Mr. Rangel’s proposed 4% surtax on adjusted gross income above $200,000 for couples and $150,000 for singles. But here’s an intriguing alternate explanation — maybe what scared Mrs. Clinton away from the Rangel plan wasn’t the tax increases but the tax cuts.

We’re particularly interested in two provisions of Mr. Rangel’s tax plan, which is named the “Tax Reduction and Reform Act of 2007.” The first is a reduction in the corporate income tax, to 30.5% from the current 35% level. That would still leave America’s corporate tax rate the fourth-highest in the world and above the average rate for countries other than America that are members of the Organization for Economic Cooperation and Development, which is 28.1%, according to the Tax Foundation. Mr. Rangel, who is chairman of Ways and Means, estimates the cost of the reduction of the corporate tax rate at $363.84 billion over ten years.

This newspaper favors the elimination of the corporate income tax. It’s a form of double taxation, since the same income is already taxed when it is passed along to shareholders as dividends. The tax is paid, in the end, by the customers of corporations. But for the moment, as a matter of tactics, advocates of tax cuts can seize on the fact that the top tax-writer among the Democrats has put himself on the record in favor of a nearly 13%, $363.84 billion tax reduction to profitable American companies such as Exxon-Mobil and Goldman Sachs. It’s a step in the right direction.

It’s also an opportunity for Republicans to press Mrs. Clinton on whether she backs this part of the Rangel plan or whether she opposes it, and if so, why? She emerged in the last debate as something of a laughing stock for the way she evaded giving meaningful answers. So this is a way to pin her down. It’s also a good question for the other presidential candidates.

The second element of the Rangel tax plan that caught our eye was that he would give the largest tax cuts — an average of $3,582 for each filer, according to an analysis by the Tax Policy Center of the Brookings Institution and the Urban Institute — to households earning between $200,000 and $500,000 a year. The accompanying chart tells the story. Those reductions are net of the 4% surtax. These are taxpayers whom Democratic presidential candidates have been labeling as “the rich” and on whom threatening to raise taxes.

In other words, the chief Democratic tax writer has now put himself on record to the effect that families earning between $200,000 and $500,000 a year should get a big additional tax cut. As the Tax Policy Center analysis puts it, those in the top 5% of income earners but not in the top 1% of income earners see an average tax cut equal to 1.8% of income under the Rangel plan. Sounds good to us.

We disagree with Mr. Rangel’s plan to pay for the tax cuts on the $200,000 to $500,000 earners by raising tax rates on the $1 million earners. But the principle that those earning $200,000 to $500,000 are not “rich” and deserve substantial additional tax relief is one upon which, as a matter of strategy and tactics, the tax-cutting forces would be wise to seize. Republicans can press Mrs. Clinton on whether she backs this principle of the Rangel plan. If not, why? It’d also be a good question for the other presidential candidates.

Democrats in Congress dealt for years with Republican administrations proposing tax reform compromises by accepting the tax increases offered by the Republicans and rejecting the tax cuts. Now the Republicans have the opportunity to turn the tables on Mr. Rangel by accepting his plan to cut taxes on corporations and on those earning between $200,000 and $500,000 a year and rejecting his tax increases. In a political environment in which the Republicans are a minority in the Congress and stand a risk of losing the White House, better to seize on tax cuts being offered by Mr. Rangel and enact them than to reject his proposal in its entirety and risk getting no tax cuts at all.