During the 2012 presidential campaign, Republican candidates Mitt Romney and Paul Ryan proposed a simple solution to the tax code that called for a lower rate, but with a cap on deductions of $17,000.
There were no exceptions—including charitable deductions. Nonprofits were outraged, saying the limits on charitable giving, which the Congressional Budget Office said ranks among the largest categories of personal deductions, would kill donations.
Now, however, House Budget Chairman Ryan says charitable deductions should be protected. In an interview with CNBC, Ryan said charitable deductions are the "one exception" he would make to any deduction limit or cap as part of simplifying the tax code.
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"This is really the one exception I make this for," he said. "Charities ought to be a tax expenditure that is still preserved because civil [society] is one of the most important components of American life, of getting people involved in our communities and philanthropies. I think that is a very important thing to preserve and that's pretty much as a supply side or a low tax-rate guy."
Ryan's change in opinion is important not only because it varies from his previous stance, but because he is being cited as a possible presidential candidate in 2016. (Ryan told CNBC that he'll make a decision about whether to run in 2015.) He also sits on the Ways and Means Committee, which handles tax legislation.
The Wisconsin Republican also talked about the need to lower the corporate tax rate and simplify the corporate tax code to make America's companies more competitive.
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"In the global economy we are in, when we tax our employers at much higher tax rates than our foreign competitors are taxing theirs, it's putting us at a competitive disadvantage and it's slowing down our economy," he said. "And if we do pro-growth economic policies that actually help create jobs and growth, we will have more revenues coming into the government. It's not a fantasy, it's pretty well documented."
—By CNBC's Robert Frank