Simplified, Manageable, And Responsible Tax Act or the SMART Act This bill replaces the marginal income tax rates in the Internal Revenue Code with a single rate of 17% on individual taxable income. The bill redefines taxable income to mean the amount by which wages, retirement distributions, and unemployment compensation exceed the standard deduction. It also increases the basic standard deduction, includes an additional standard deduction for dependents, and includes the taxable income of each dependent child under the age of 14 in an individual's taxable income. The bill revises the tax on corporations to (1) replace it with a tax on every person engaged in a business activity equal to 17% of the business taxable income of such person; and (2) make the person engaged in the business activity liable for the tax, whether or not such person is an individual, a partnership, or a corporation. The bill imposes on employers a 17% tax on the value of excludable compensation provided during the year to employees. With respect to pension rules, the bill (1) repeals rules relating to non-discrimination, contribution limits, and restrictions on distributions; and (2) revises rules relating to transfers of excess pension assets. The bill also repeals the alternative minimum tax; all income tax credits; estate, gift, and generation-skipping transfer taxes; and income tax provisions, except certain provisions relating to retirement distributions and tax-exempt organizations. The bill prohibits Congress from considering legislation to make specified changes to tax policy unless Congress waives or suspends the prohibition with a three-fifths vote.