Far from being a $5 trillion tax cut, Republican presidential nominee Mitt Romney’s tax plan could end up increasing federal government revenue, based on a new analysis highlighted in the latest Barron’s. Romney wants to cut individual tax rates by 20 percent while eliminating deductions. Romney would “extend the Bush tax cuts, end the alternative-minimum tax, lose the extra income taxes from Obamacare and cut income-tax rates to a range of 8% to 28% from the current 10% to 35%.” The Romney campaign calls its plan revenue-neutral.

But Brian Wesbury, chief economist of First Trust Advisors, has calculated that the plan could actually increase tax receipts in 2015 by $145 billion, and even more if tax cuts stimulate economic growth.

Based on the latest IRS data from 2009, Wesbury projects that individual income-tax receipts would total $1.4 trillion in 2015, the earliest a Romney plan might be implemented. Adding back $1.7 trillion of itemized deductions to taxable income and taxing it at 25% — the average tax rate on higher earners — would raise $425 billion in revenue. Wesbury figures the lower tax rates would cost the Treasury $280 billion in revenue, resulting in $145 billion in added receipts from Romney’s plan. And, he estimates that the new rates would stimulate the economy, adding $120 billion more to Uncle Sam’s coffers.

If you can’t fathom how that scenario might work, you might need a refresher course in supply-side economics.