And, when the special tax provision is a deduction or exclusion, the tax benefit is greater for those in higher brackets.

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But note again that the largest group excluded from paying income tax because of special tax expenditures are seniors, who get a bigger standard deduction than younger folks and more importantly, special tax treatment for their Social Security benefits.

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Including the charitable tax deduction in a grand bargain tax cap would fail to recognize the fundamental difference between special interests and philanthropy.

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