Newt Gingrich, in his bid for the GOP presidential nomination, proposed a 15 percent flat tax. Texas Gov. Rick Perry, another former GOP presidential aspirant, proposed a 20 percent tax.
"If you pay a flat tax, you know what your tax is going to be. . . . The people who work and make more," Smith said, "they are paying more."
Smith's flat tax would not be truly flat. He said he would allow exemptions for mortgage interest, charitable giving, and student-loan interest, all features of the current tax code beloved by the middle class.
He would do away with federal taxes on capital-gains investment income.
He said he would consider having no tax for the poor, but declined to say what income level should qualify for such an exemption. That could depend "on how well we do in getting this debt under control," he said.
Smith's economic plan also included calls for less federal regulation of business, repeal of the Affordable Care Act, and passage of a constitutional amendment requiring a balanced budget set at no more than 20 percent of gross domestic product.
The news conference, at the Crowne Plaza hotel, was the first of several across the state in which Smith plans to tout his economic ideas. His campaign said he would be rolling out other policy proposals in coming weeks as he seeks to defeat Democratic Sen. Bob Casey, in office since 2007.
Smith, from coal country northeast of Pittsburgh in Armstrong County, called for increased energy production in Pennsylvania, where he said 40 percent of electrical power was generated from coal.
A former coal company executive, he decried what he said was excessive regulation of mining by the U.S. Environmental Protection Agency.
"Things will get worse if the president is reelected," he said. "The EPA will run even more out of control. And Bob Casey - Senator Zero - will do what he always has done: nothing."
Larry Smar, speaking Wednesday on behalf of Casey, said Smith's economic positions "are out of the tea party playbook and to the right of [Mitt] Romney."
Smar said Smith would "raise taxes on middle-class families while cutting taxes for the wealthiest Americans - especially when combined with Smith's call to eliminate capital-gains taxes."
Contact Tom Infield
at 610-313-8205 or email@example.com, or follow on Twitter @tinfield.