The McCain campaign has said it will release Sarah Palin’s tax returns and when it does, tax attorneys will have their pencils sharp and ready to go over the numbers.

Several tax accounting blogs have raised the question: should Sarah Palin pay federal income taxes on the per-diem payments that she received from the state of Alaska for nights spent in her Wasilla, Alaska, home?

Anthony C. Infanti, a professor of tax law at the University of Pittsburg law school, raised the issue in a blog called “Feminist Law Professors.” Mr. Infanti writes that if Governor Palin was not engaging in business while in Wasilla, but simply preferring to spend the nights there, then the per diem payments would be taxable income.

“If these are really just personal expenses paid by her employer, that sounds like taxable income to me,” Mr. Infanti wrote in his posting.

Ms. Palin received around $17,000 in per diem payments from the state for 312 nights she spent in her Wasilla home rather than the Governor’s mansion in her first 19 months in office. Per diem payments are a daily allowance to cover meals and lodging while on the state’s business.

Kim Garnero, the Alaska director of finance, has said that the state does not consider the payments to Ms. Palin to be taxable income at the federal level. But others, besides Mr. Infanti, differ. One of them is Robert S. McIntyre, director of the Citizens for Tax Justice, a labor-backed group whose calculations are widely respected by tax experts.

“It’s obvious that the per diems are taxable income. There’s no question it is taxable,’’ Mr. McIntyre said. “If it were not taxable, no one would pay taxes. People would convert their salary into a per diem and no one would pay taxes. You can deduct travel expenses when away from home. But you cannot deduct travel when you are at home.”

Mr. Infanti also raises another question, over the airfare reimbursements from the state for Ms. Palin’s family members. This gets into the issue of whether such fringe benefits are taxable income. In his blog posting, Mr. Infanti notes that the Joint Committee on Taxation, after examining the tax returns for President Richard Nixon, concluded that Mr. Nixon should have included the value of air travel on government jets for his family members as part of his gross income.