Key neo-conservatives and other right-wing hawks who championed the 2003 U.S. invasion of Iraq are calling for military strikes against Iran in retaliation for its purported murder-for-hire plot against the Saudi ambassador here.

Leading the charge is the Foreign Policy Initiative (FPI), the ideological successor to the Project for the New American Century (PNAC), which played a critical role in mobilising support for "regime change" in Iraq in the late 1990s and subsequently spearheaded the public campaign to invade the country after the 9/11 attacks. The group sent reporters appeals by two of its leaders for military action on its letterhead Monday. 

In a column headlined "Speak Softly …And Fight Back" in this week's Weekly Standard, chief editor William Kristol, co-founder of both PNAC and FPI, said the alleged plot amounted to "an engraved invitation" by Tehran to use force against it.

"We can strike at the Iranian Revolution Guard Corps (IRGC), and weaken them. And we can hit the regime's nuclear weapons program, and set it back," he wrote, adding that Congress should approve a resolution authorising the use of force against Iranian entities deemed responsible for attacks on U.S. troops in Iraq and Afghanistan, acts of terrorism, or "the regime's nuclear weapons program".

Kristol's advice was seconded by Jamie Fly, FPI's executive director, who called for President Barack Obama to emulate former presidents Ronald Reagan and Bill Clinton when they ordered targeted strikes against Libya in 1986 and Iraq in 1993, respectively, in retaliation for alleged terrorist plots against U.S. targets.

"It is time for President Obama to follow in the footsteps of his predecessors and stand up to tyrants who kill Americans and threaten our interests," wrote Fly, who served on the National Security Council staff and the Pentagon under George W. Bush, in the on-line edition of The National Review.

"It is time to take military action against the Iranian government elements that support terrorism and its nuclear program. More diplomacy is not an adequate response," he wrote.

The FPI appeals, which have been echoed by other former Iraq war hawks, such as Bush's former U.N. ambassador, John Bolton, and Reuel Marc Gerecht at the neo-conservative Foundation for Defense of Democracies (FDD), came as analysts here continue to debate the credibility of the alleged plot against Saudi Amb. Adel al-Jubeir and how to react to it if, as the administration contends, it was authorised at a high level in Tehran. 

The likelihood that the plot was indeed real - and, if so, whether it gained high-level authorisation - has been widely questioned, mainly by two sets of experts here. 

Reaction among virtually all Iran specialists, including former government and intelligence personnel, has ranged from outright scepticism to bewilderment over what, if the alleged plot was actually consummated, Tehran would have hoped to gain from assassinating the Saudi ambassador on U.S. soil. 

"(N)othing short of mind-boggling," wrote Vali Nasr, a senior fellow at the Brookings Institute, in reaction to the alleged plot. "If true, this plot shows a monumental lapse in judgment on Tehran's part, an audacious and reckless adventurism that will go down as the clerical regime's colossal mistake that will weaken its hand internationally and even unravel its grip on power…" 

Counter-terrorist experts knowledgeable about Iran's Quds Force, the elite unit of the Islamic Revolutionary Guard Corps (IRGC) accused of sponsoring the scheme, have been even more sceptical that it would rely on an untested Iranian-American used-car salesman to make contact with a purported member of the Zetas drug cartel in Mexico to arrange the assassination.The supposed Zeta contact turned out to be an informant for the U.S. Drug Enforcement Administration (DEA), according to the complaint released with great fanfare last week by the attorney general. 

"Fishy, fishy, fishy," said Bruce Riedel, a Central Intelligence Agency (CIA) veteran who was formerly in charge of the Near East and South Asia on the National Security Council, when asked to characterise his assessment, while Robert Baer, a former Middle East CIA field officer, compared the plot as outlined by the complaint to a "truly awful Hollywood script". 

"None of it measures up to Iran's unsurpassed skill in conducting assassinations," he wrote on Time magazine's website. 

"Why on earth would they create a situation in which they had to rely on this untested, untrained, unguided, and uncontrolled asset rather than their own people?" wrote Col. Pat Lang (ret.), the Defense Intelligence Agency's former top Middle East and South Asia analyst on his Sic Semper Tyrannis blog. 

Calling the government's case "trash", Lang added that, "The overwhelming likelihood is that this is someone's 'information operation' intended to condition public attitudes for some purpose." 

Such scepticism, however, has not deterred the administration, key lawmakers, or former Iraq hawks from calling for a stern response. 

Indeed, Obama himself said Thursday that he will push for "the toughest sanctions" against Iran on the part of the U.S. allies and the U.N. Security Council, while senior Treasury officials testified that they were considering blacklisting Iran's central bank, a move that enjoyed strong bipartisan support in Congress, notably from lawmakers most closely associated with the Israel lobby, even before the alleged plot was disclosed. 

But a number of former Iraq hawks, few of whom appear to entertain much doubt about the plot's seriousness or provenance, are calling for military action. 

"More sanctions aren't a bad idea…," wrote Gerecht, a major proponent of invading Iraq when he was at the American Enterprise Institute (AEI), in a column published Friday by the Wall Street Journal's staunchly neo-conservative editorial page. "But they will not scare (the regime). The White House needs to respond militarily to this outrage. If we don't we are asking for it." 

Another Iraq war booster, Andrew McCarthy, also of FDD, joined the chorus in the National Review Online: "There is a range of possible political responses, of course, but given its three-decade campaign of aggression, the response to Iran must be military - and decisive. The regime must be destroyed." 

Monday's appeal by FPI for military action was perhaps more remarkable, if only because three of the group's four directors - Eric Edelman, Robert Kagan, and Dan Senor - were recently named as key advisers to Mitt Romney, the frontrunner for the 2012 Republican presidential nomination. 

Like Kristol, Kagan was a co-founder of both PNAC and FPI and a critical advocate of invading Iraq, while Senor served in Iraq after the invasion as a top official in the Coalition Provisional Authority. Edelman, who, as ambassador to Turkey at the time, lobbied its military to support the 2003 invasion, went on to serve as undersecretary of defence for policy under former Pentagon chief Donald Rumsfeld. 

Although Romney has remained silent to date on how Washington should respond to the alleged plot, a number of his other advisers who championed the Iraq invasion have long called for the U.S. to make the threat of military action against Iran more credible. 

In his first major policy address two weeks ago, Romney himself called for two aircraft carrier task forces to be permanently deployed in the region as a deterrent to Tehran.