uh, I think it allows anyone to do so...it's just not worth it in states that have income tax burdens higher than sales tax. You get one or the other, right?
I don't think you get my point. Let's say two people living in two different states have a state/local tax burden of $10,000. In state A, the breakdown is $5,000 in state income tax, $3,000 in property tax and $2,000 in sales tax. In state B, the breakdown is $5,000 in property tax and $5,000 in sales tax and there is no income tax.
The resident of state B gets to deduct 100% of the tax burden from the federal tax return. The resident of state A gets to deduct either $8,000 (income + property) or $5,000 (sales + property), but cannot deduct the entire $10,000.
NOT FAIR!