What if separated couple can't agree on itemizing

[Dave918]

What happens if a separated couple (not legally separated but living apart) can't agree on itemizing? What happens if one spouse itemizing on their return and the other one takes the standard deduction? Thank you

[bluedeb]

You most likely will hear from the IRS about not using the same standard deduction or itemized deductions.

When filing separately, both spouses must take the standard deduction or both must itemize their deductions. One spouse cannot itemize their deductions while the other spouse takes the standard deduction. When itemizing deductions, each deduction can only be used by one spouse even if both spouses paid for the expense.

When filing as Married Filing Separately:

• Filing separate returns in such a situation may be beneficial if it allows you to claim more of your available medical deductions by applying the threshold to only one of your incomes.
• When filing separately, both spouses must take the standard deduction or both must itemize their deductions. One spouse cannot itemize their deductions while the other spouse takes the standard deduction.
• When itemizing deductions, each deduction can only be used by one spouse even if both spouses paid for the expense. A deduction can be split between spouses filing separately as long as the total claimed by both spouses does not exceed the total deduction.

[MaryK4]

If you and your spouse file separate returns and one of you itemizes deductions, the other spouse must also itemize, because in this case, the standard deduction amount is zero for the non-itemizing spouse.  This means that if you both agree, you can use the standard deduction, but one spouse can decide to itemize and force the other spouse to itemize, even if they have zero itemized deductions.

[Mike9241]

the tax rules say itemizing takes precedence over the standard deduction. so if both don't agree on what to use it's the taxpayer that took the standard deduction that is going to lose. 

per the IRS

If you and your spouse file separate returns and one of you itemizes deductions, the other spouse must also itemize, because in this case, the standard deduction amount is zero for the non-itemizing spouse.