Per the IRS 501 publication; Electing to itemize for state tax or other purposes. Even if your itemized deductions are less than your standard deduction, you can elect to itemize deductions on your federal return rather than take the standard deduction. You may want to do this if, for example, the tax benefit of itemizing your deductions on your state tax return is greater than the tax benefit you lose on your federal return by not taking the standard deduction. To make this election, you must check the box on line 18 of Schedule A.
I'm allowed to itemize my federal return because my state tax return is greater than losing the federal return by not taking the standard deduction.
