In the days since the Justice Department unveiled its charges of an Iranian plot to assassinate the Saudi ambassador to Washington, conservative pundits have dusted off their attack Iraq language from 2003 and begun to apply it to Iran. It didn't take long for many to advocate a military response to Iran, in some cases not just against the revolutionary guard members believed responsible for the plan but also against Iran's nuclear program. The martial rhetoric from inveterate hawks was predictable. But even President Obama suggested that the United States would not take any "options off the table," a phrase that is understood to leave open military options.

They should not be. Even assuming the worst -- Iranian Government involvement at the most senior levels -- a military response is just what it was before the plot became known: a dangerous and unpredictable option that should be avoided.  

Much remains unclear about the alleged terrorist plot itself. According to the Justice Department, an Iranian-American used-car dealer and his cousin, an operative of the Quds force of Iran's Revolutionary Guard Corp, are at the center of a bizarre, sloppy and, audacious terrorist plot to assassinate the Saudi ambassador to the United States. A large number of experts on Iran have expressed skepticism about the plausibility of these allegations. Still, the U.S. Government clearly believes Iran is responsible. The Obama administration has made public accusatory statements that can hardly be walked back at this point, and it is difficult to believe that it would have staked its reputation on a flimsy case.  

If the Justice Department has the story right, and if the clerical regime actually had knowledge of the plot, Iran has crossed a dangerous redline. As bad as United States-Iranian relations are now, they are bound to get worse. Only evidence that leads the administration to back down on its claims -- an unlikely scenario -- could avert at this point a serious escalation in United States-Iranian tensions.

The public exposure of this plan, coming alongside continued Iranian progress on its nuclear program and United Nations reports of egregious human rights abuses, may have been meant to show toughness against Tehran and to build international support for sanctions. But it has also created new opportunities for advocates of the military strike option to more forcefully press their case. In a presidential campaign season in which potential Republican candidates are searching for ways to attack Obama and to differentiate themselves from each other, all the incentives push toward ever more hawkish public rhetoric. It is not clear that the administration anticipated the political pressure that is now being mustered to demand a forceful response that matches the severity of these allegations.

The escalation has already started with U.S. efforts to increase international economic and diplomatic isolation of Iran. However, such efforts are likely to face resistance from critical countries like Russia and China, particularly as U.S. officials lack or are unwilling to expose indisputable intelligence to implicate Iranian officials in the plot. The difficulty of garnering sufficient international support for effective sanctions will now be associated with a failure to adequately respond to what lawmakers across the political spectrum have called an act of war against the United States.

Military alternatives will again very likely become part of the Washington conversation, even if senior U.S. officials had previously all but ruled them out (and encouraged Israel to do the same). At this stage, there is little chance of retaliatory U.S. military action. Pentagon officials have already issued statements suggesting this incident requires a diplomatic and legal response. But if such responses appear lackluster and ineffective, political pressure will mount to make military options more credible. At the very least, Israeli and Saudi officials who favor military strike options against Iran's nuclear program may now receive a more receptive audience in Washington.

The sad reality is that there is no silver bullet solution to the Iranian challenge, and a creative combination of engagement, containment, and deterrence will likely be necessary to address it. Despite this new plot twist, a military strike remains among the worst options possible, whether it comes from the United States or Israel, as the United States will be implicated either way.

First, the operational challenges of a military attack remain daunting. Iran's nuclear facilities are widely dispersed and deeply buried and so difficult, if not impossible, to eliminate. An Israeli attack would be even more challenging, though not impossible, due to long distances to Iranian targets and over flight challenges. Second, and more significantly, the aftermath of an attack could be devastating militarily and politically. It could unleash a wave of Iranian retaliation against U.S. forces, allies, and interests. Iran maintains a wide array of levers across the region, including militia groups it has trained and funded, that it could employ to retaliate against U.S. forces or diplomatic personnel, particularly in countries like Iraq. Iranian missiles have ranges that can reach Israel and all its Gulf Arab neighbors, including those hosting U.S. military forces. Such an attack could also backfire by fomenting nationalist sentiment within Iran (particularly if large numbers of civilians are killed) and boost support for more hard-line elements within the regime that current policies are attempting to marginalize. It could also increase Iranian incentives to obtain nuclear weapons to avoid such attacks in the future, while undermining painstaking U.S. efforts to bolster international and regional support for economic and diplomatic pressure against Iran. In short, there are serious risks associated with this option with little potential to actually solve the problem, and possibly making it harder to solve in the future.

A military strike would be particularly damaging in a post Arab spring environment, in which public opinion is already hostile toward U.S. policies. Even if Arab governments may quietly welcome forceful U.S. actions, Arab publics are far more sympathetic to Iran's anti-Western positions. Despite Iran's waning regional influence as Arab revolts and Turkish activism have decreased its relevance in the resistance narrative, Arab publics would likely rally behind Iran in the face of an attack. Additionally, they could constrain their governments' ability to support US-backed efforts to isolate Iran.

Some may view the assassination plot as an opportunity to bring the military option back to the table, believing that only a forceful response to Iran's actions will prevent the country from striking again. However this type of response would be a strategic mistake. A military attack would isolate the United States rather than Iran, further weakening U.S. influence regionally and globally while giving an increasingly isolated and vulnerable Iran a second chance.

Dalia Dassa Kaye is a Visiting Professor and Fellow at UCLA's International Institute and Burkle Center for International Relations.