Romney has proposed a 20% rate cut and limiting deductions to $17,000 or $25,000 or $50,000, depending how generous he’s being with imaginary money that day. So, would such a tax reform be revenue neutral, or even raise revenue?
Eliminating all itemized deductions would yield about $2 trillion of additional revenue over ten years if we cut all rates by 20 percent and eliminate the AMT. Capping deductions would generate less additional revenue, and the higher the cap, the smaller the gain. Limiting deductions to $17,000 would increase revenues by nearly $1.7 trillion over ten years. A $25,000 cap would yield roughly $1.3 trillion and a $50,000 cap would raise only about $760 billion.
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Without more specifics, we can’t say how much revenue such limits would actually raise. But these new estimates suggest that Romney will need to do much more than capping itemized deductions to pay for the roughly $5 trillion in rate cuts and other tax benefits he has proposed.
So, even at its best, Romney is talking about cutting revenue by about $300B per year. Like, say, cut Medicare benefits by nearly half. That would do it.