How can I enter Foreign Taxes Paid but declare 0 reduction in foreign taxes? TurboTax won't let me make this combination for some reason.

it depends. There is a screen as you are going through the interview that asks if there is a reduction in foreign taxes. It is one of the screens that you will navigate to during the interview. This is a screenshot what it should look like. If there is no reduction in foreign taxes though, why would you enter this?