The nonpartisan, Washington-based Congressional Budget Office said that the mortgage-income tax deduction cost $80 billion in 2009.
The vote on the mortgage-interest issue came after the platform panel approved an amendment calling for the preservation of deductions for charitable contributions.
Talent said advocating for the charitable deduction contradicted the principle of a simpler tax code. "I felt that was an exception that we could make without getting into other specifics," Talent said in an interview.
Tax simplification is also a stated goal of House Republicans, who last month passed a measure setting up procedures to debate and adopt overhaul legislation.
U.S. Representative Marsha Blackburn of Tennessee, a co- chairwoman of the platform committee, said she anticipates that Romney will offer soon a more specific tax-overhaul proposal, possibly during the convention.
The panel, formally known as the Committee on Resolutions, is scheduled to vote tomorrow on the entire platform to be submitted to the full convention.