Some of the possible fiscal cliff solutions could decrease donations to charities.

The Charitable Giving Coalition has sent letters to President Obama and lawmakers, urging them to protect the tax deduction for givers.

The White House has proposed capping all itemized deductions at 28 percent for certain taxpayers. A bipartisan debt reduction panel has also proposed eliminating the deduction and replacing it with a tax credit.

A study by the fundraising firm Dunham and Company shows most Americans favor the charitable tax deduction and would donate less if it was eliminated.