Sen. Sam Brownback's presidential campaign hasn't gained much traction, but one proposal from the Kansas Republican sure deserves some: the optional flat tax.

Brownback has suggested an ingenious way taxpayers could bypass the convoluted Internal Revenue Code. Under his plan, Congress would simply pass legislation that would give personal income-tax filers a choice: Stick with the current 1040 system and its record-keeping nightmares, or file a different tax form that would apply a single rate (perhaps 15 percent or 20 percent) to all income above an inflation-adjusted threshold. He suggests $20,000 for single filers, $40,000 for married couples.

Those who picked the flat tax would receive no further exemptions - not for mortgages, charitable contributions, education expenses, etc. Every taxpayer would still have to withhold taxes from their paychecks or deposit estimated taxes quarterly if they're self-employed.

But those who chose to do so could, as the saying goes, file their income taxes April 15 on a form the size of a postcard. The healthy standard deduction should provide significant tax relief for low- and middle-income workers. And the plan would not require a numbing debate about tax reform.

A report from the Tax Foundation estimated that individuals spent $111 billion complying with the federal income tax code in 2005. So even if Sen. Brownback's presidential run makes few headlines, his tax proposal deserves a wider audience.