For the Obama Democrats, a tax cut is no longer letting you keep more of what you earn. In their lexicon, a tax cut includes tens of billions of dollars in government handouts that are disguised by the phrase "tax credit." Mr. Obama is proposing to create or expand no fewer than seven such credits for individuals.

Here's the political catch. All but the clean car credit would be "refundable," which is Washington-speak for the fact that you can receive these checks even if you have no income-tax liability. In other words, they are an income transfer — a federal check — from taxpayers to nontaxpayers. Once upon a time we called this "welfare," or in George McGovern's 1972 campaign a "Demogrant." Mr. Obama's genius is to call it a tax cut.

The Tax Foundation estimates that under the Obama plan 63 million Americans, or 44% of all tax filers, would have no income tax liability and most of those would get a check from the IRS each year. The Heritage Foundation's Center for Data Analysis estimates that by 2011, under the Obama plan, an additional 10 million filers would pay zero taxes while cashing checks from the IRS.

The total annual expenditures on refundable "tax credits" would rise over the next 10 years by $647 billion to $1.054 trillion, according to the Tax Policy Center. This means that the tax-credit welfare state would soon cost four times actual cash welfare. By redefining such income payments as "tax credits," the Obama campaign also redefines them away as a tax share of GDP. Presto, the federal tax burden looks much smaller than it really is.

There's another catch: Because Mr. Obama's tax credits are phased out as incomes rise, they impose a huge "marginal" tax rate increase on low-income workers. The marginal tax rate refers to the rate on the next dollar of income earned. As the nearby chart illustrates, the marginal rate for millions of low- and middle-income workers would spike as they earn more income.

Some families with an income of $40,000 could lose up to 40 cents in vanishing credits for every additional dollar earned from working overtime or taking a new job. As public policy, this is contradictory. The tax credits are sold in the name of "making work pay," but in practice they can be a disincentive to working harder, especially if you're a lower-income couple getting raises of $1,000 or $2,000 a year. One mystery — among many — of the McCain campaign is why it has allowed Mr. Obama's 95% illusion to go unanswered.