WASHINGTON — This year's Republican presidential candidates are using domestic food aid as an example of a welfare state gone awry.

Supporters of the program say it is one of the most reliable safety nets for families who find themselves unable to pay for food, and politically the program has proved almost untouchable over many decades.

Republican presidential candidates Mitt Romney, Rick Santorum and Newt Gingrich say the government should stop and convert food stamp spending to block grants to states, a move that could freeze spending and cut the benefit to many who now receive it.

Gingrich, the former House speaker, and Santorum, a former Pennsylvania senator, were both heavily involved in congressional welfare reform efforts in the mid-1990s