Having a revocable trust does not necessarily mean that you will not have to pay Estate Taxes. A revocable trust is a tool that can allow married couples, by effectively planning their estates, to prevent wasting one of their lifetime exemptions to reduce or eliminate Estate Taxes. Each spouse can leave an unlimited amount tax-free to a surviving spouse who is a U.S. Citizen. This is called the marital deduction. Use of the marital deduction defers Estate Taxes until the second spouse dies.