Newt Gingrich was one of several candidates during Saturday night's Republican presidential debate who embraced the idea of the United States using covert operations to help solve diplomatic problems in Iran. (Reuters)

During a Republican presidential debate Saturday night, several candidates embraced the idea of the United States using covert operations to help solve diplomatic problems.

Some of the activities they suggested may be underway but not publicly acknowledged.

Former House speaker Newt Gingrich (Ga.) has long been an advocate of using the CIA in Iran, and he pushed that during the South Carolina debate. Asked what “non-war means” the United States could employ to deal with Iran’s apparent nuclear weapons program, Gingrich said he would institute “maximum covert operations to block and disrupt the Iranian program, including taking out their scientists, including breaking up their systems, all of it covertly, all of it deniable.” He also called for “maximum coordination with the Israelis in a way which allows them to maximize their impact on Iran.”

Last winter, news reports described a sophisticated computer worm named Stuxnet that set back Iran’s nuclear program. Although it was never confirmed, the worm was attributed to Israeli and U.S. intelligence.

In November 2010, there were reports from Tehran that Majid Shahriari, a top Iranian nuclear scientist, had been killed and that another, Fereydoon Abbasi Davani, had been wounded. The Iranian government accused the Mossad, the Israeli intelligence agency, and the CIA.

Two months later, the Iranian government accused the Mossad and the CIA of killing Masoud Ali Mohammadi, another Iranian nuclear scientist, in Tehran. In July 2010, a nuclear researcher named Shahram Amiri appeared in Tehran and said that he had been kidnapped by CIA agents in Medina and held for more than a year in the United States. American officials said later that he had defected to the United States and then changed his mind.

The CIA has declined in the past to comment on these events.

Gingrich said later in Saturday’s debate that he would use “mostly covert” steps to assist in the removal of Syrian President Bashar al-Assad, without specifying what they would be.

Gingrich is no novice in these matters. In 1995, he publicly called for the Clinton administration to have the CIA undertake covert actions to undercut the Iranian regime. He later had $18 million inserted into the secret portion of the intelligence authorization bill to carry on a black propaganda program against Tehran.

During the debate, former Massachusetts governor Mitt Romney also took up the idea of covert operations in Iran. After the contested 2009 Iranian presidential election, Romney said President Obama should have spoken out publicly “when dissidents took to the streets and say, ‘America is with you.’ ” Romney called for working “on a covert basis to encourage the dissidents.”

The CIA’s recent record of carrying out such activities in the Middle East is not great. In 1991, after Iraq’s forces under Saddam Hussein were forced out of Kuwait, then-President George H.W. Bush publicly encouraged Shiite opponents of the Iraqi dictator to come out against him. At the same time, covert operations were undertaken to force him from power.

Hussein carried out brutal attacks against the dissidents, particularly in southern Iraq. Although the United States eventually set up air cover to protect the Iraqis, the covert operations were unsuccessful. One program supplied initial funding to the ­exile group headed by Ahmed Chalabi, who later got Congress to fund his group after the CIA cut him off.

Candidate Herman Cain said, “The first thing that I would do is to assist the opposition movement in Iran that’s trying to overthrow the regime. Our enemies are not the people of Iran. It’s the regime. And a regime change is what they are trying to achieve.”

When asked whether that meant he would provide military assistance to the opposition, he replied, “No, not at this time,” but he did not specify what kind of support he would provide.