The Republican presidential candidates clashed over how to treat millions of illegal immigrants in the U.S., after Newt Gingrich called for a “humane” policy that would allow those in the country for 25 years and with established family and community ties to remain.

The candidates also sparred over how to deal with Iran’s nuclear program, extending the USA Patriot Act, defense spending cuts, wars and terrorism during the two hour national security debate in Washington at DAR Constitution Hall, a short walk from the White House.

Former House Speaker Gingrich, enjoying a surge in the polls, said he was “prepared to take the heat” for advocating a policy that, while deporting recent illegal immigrants, would make an exception for those who came long ago and laid down roots. Many Republican primary voters regard any such exception as amnesty for lawbreakers.