Reporting from Washington— One of the most treasured tenets of the Republican Party — "No new taxes" — has been thrown open to debate by a simple question: What, exactly, is a new tax?

The answer, argues Grover Norquist, the godfather of contemporary anti-tax conservatism in Washington, is anything that increases federal revenue. Thus, closing loopholes that have allowed corporate giants and millionaires to slice away at their tax bills would constitute an unacceptable new tax — unless a comparable tax cut is made elsewhere.

But other views are emerging. Worried about the nation's treacherous deficits, some in the GOP say that stanching the $1 trillion lost each year to individual and corporate deductions and breaks is vital to the nation's fiscal health.

The schism has launched an epochal battle for the fiscal soul of the GOP, a party that has steadfastly followed the "no new taxes" credo for a generation.