Most Republican presidential candidates, as well as chronic non-GOP hawks such as Sen. Joe Lieberman (I-CT), are beating the drums for enhanced covert action against Iran. That strategy has both a narrow application and a broad application. The narrow version proposes to use measures ranging from electronic sabotage to assassinating Iranian nuclear scientists to undermine Tehran’s nuclear program. The broader version seeks to use a variety of methods to oust the clerical regime from power.

Caution is warranted regarding both levels—but especially the broad regime-change strategy. One can make a decent case for trying to slow Tehran’s apparent quest for nuclear weapons. A nuclear-armed Iran would be an uncomfortable neighbor not just for Israel but for most countries in the Middle East and Southwest Asia. And it would not benefit the security interests of the United States to have membership in the global nuclear-weapons club expand—especially when a new member is an unpredictable, authoritarian state.

Yet even with the relatively narrow agenda of putting obstacles in the way of Tehran’s nuclear program, there are troubling issues, most notably the killing of scientists. Moreover, support for the nuclear agenda goes far beyond the clerical elite. After all, Iran’s original effort to develop a nuclear arsenal began under the shah in the 1960s, not the mullahs after the 1979 Revolution. A substantial segment of the Iranian population could deeply resent Washington’s sabotage of a program that is a source of national pride.

But the potential for blowback from efforts to thwart Iran’s nuclear ambitions is mild compared to the likely consequences from a CIA-directed operation to achieve regime change. Washington has been down this road before, working with British intelligence agencies to overthrow Iran’s democratic government and restore the autocratic, brutal shah to power in 1953. Iranians have long memories, and that episode is still a source of great anger. Even portions of the population who loathe the mullahs are not likely to welcome a new round of Washington’s meddling in their country’s internal affairs.

In the recent foreign-policy debate among GOP presidential candidates, Mitt Romney chastised President Obama for not expressing public support for anti-regime forces in Iran and showing that “America is with you.” That view is naïve at best and delusional at worst. Given the long, troubled history of relations between Iran and the United States, a public embrace of political reformers by Washington could be the kiss of death for those brave individuals. Domestic opposition to the repressive clerical regime is mounting, but that does not mean that opponents love the United States. To the contrary, many Iranians still view the U.S. government with wariness and outright suspicion. A barely disguised “covert” program to overthrow the regime—much less an ostentatious endorsement of regime opponents—would assuredly fuel that suspicion and play into the hands of the mullahs. A more cautious, restrained policy is advisable.