The United States claims that sanctions against Iran are designed to convince it to change its behavior on a range of issues, but even the language used to describe them tells a different story. Sanctions are central to the Obama administration's "dual-track" strategy – explained as a combination of pressure and engagement intended to increase US leverage at the negotiating table. As Iranians struggle with increasingly "crippling" measures, advocates are justifying the resulting pain as the alternative to war.

No single influential figure has made war with Iran seem like a prospect more than Israeli Prime Minister Binyamin Netanyahu, despite warnings against the dire ramifications from key Israeli and western security advisers. Yet it was Netanyahu who inspired more standing ovations during a May 2011 hardline speech to Congress (29 in total) than Obama did during his state of union address in January of that year, and it has been Congress that has been pushing forward the harshest measures against Iran.

While Obama criticized the "loose talk of war" that was rampant during the American Israel Public Affairs Committee (Aipac) conference in March, discussions of sanctions by the administration remain heavily focused on the punitive element – in response to ongoing pressure from Israel and a seemingly pro-Netanyahu Congress. Obama's unwillingness to match his red line on Iran (acquirement of a nuclear weapon) with Netanyahu's red line (acquirement of "breakout capability") is a key reason why relations between the two leaders remain publicly cool. At the same time, the administration's efforts to project an image of toughness toward the Islamic Republic significantly overshadow any displays of confidence-building diplomacy.

In January, the Washington Post changed the headline of an online article written by seasoned reporters three times (likely after complaints from the State Department) and altered its content, after it originally ran with "Goal of Iran sanctions is regime collapse, US official says." The final version still quoted an anonymous official saying, "another option here is that [sanctions] will create hate and discontent at the street level so that the Iranian leaders realize that they need to change their ways."

The original created a stir among well-known Iran watchers. Pro-Israel journalist Jeffrey Goldberg tweeted that "If I were an Iranian leader and read that the goal of sanctions is regime change, I'd race to build and test a nuke." From Tehran, the Washington Post's Thomas Erdbrink noted that the "US remarks will confirm hardliners' obsession with regime change – now confirmed – and strike out against dissidents [and] dig in deeper".

During the same month, White House spokesperson Victoria Nuland continued the bellicose rhetoric by saying that global support for US-led sanctions could help "tighten the noose" on the Iranian government. Then, in February, she told reporters that "sanctions are designed to make it hurt the Iranian regime."

In the face of intense pressure from Israel and Congress during the influential Aipac conference in March, Obama bragged about imposing "unprecedented, crippling sanctions" on Iran which he said is now "feeling the bite". Some staunch Israel advocates in Congress have, meanwhile, been pushing for more draconian sanctions measures, including a bill amendment proposed by Florida Republican Representative Ileana Ros-Lehtinen that would prohibit officials from even speaking to Iranian officials unless a special waiver is issued.

"US policy towards Iran has offered a lot of bark, but not enough bite," said the chair of the House foreign affairs committee last year, after proposing HR 1905, the Iran Threat Reduction Act.

Despite all this, it has been on Obama's watch that Iran has been faced with the "most punitive sanctions that have ever been levied", according to Press Secretary Jay Carney, who acknowledged in April that sanctions have also "resulted in hardship for Iranian people".

David Ignatius, known for his access to and reporting of officials' views, wrote an article in March titled "How to Sink Iran's Regime? Sanctions, Not Bombs", where he suggested that while trying to curb Israeli military action by committing to a "pressure campaign" against Iran, Obama's Iran policy could result in regime change. The "situation resembles a hunting trap that gets tighter as the prey tries harder to escape," noted the Washington Post columnist.

According to Paul Pillar, a former top CIA Middle East analyst who teaches at Georgetown University, "sanctions against Iran have come to be treated as if they are an end, rather than a means." The vast energy spent on devising and implementing them has "led people to lose sight of what this was supposed to be all about in the first place," he said. Far more violent imagery is used in policy recommendations made by some well-known Washington thinktanks, the output of which, Pillar concedes, "does affect a larger political climate in which the administration makes its policy."

Mark Dubowitz of the Foundation for Defense of Democracies (FDD), a neoconservative-dominated thinktank composed of well-known hawks, has been analogizing sanctions as "silver shrapnel" that that can "injure" Iran for years. Frequently quoted in the media, Dubowitz recently boasted to a Canadian newspaper that the FDD has shared six reports exclusively with the Obama administration and congressional committees advocating harsher sanctions on Iran.

"Sanctions that cannot starve the nuclear program could still conceivably collapse the Iranian economy, bringing on political chaos that paralyzes the nuclear program," explains a March op-ed written by FDD senior fellow Reuel Marc Gerecht. Formerly a director of the Project for the New American Century (PNAC), which is best-known for its influence over the Bush administration's Iraq policy, Gerecht also warned that "modern authoritarian states have considerable resilience and a high threshold of pain."

Yet, for all of the FDD's focus on sanctions, Dubowitz and Gerecht argue they cannot achieve the administration's stated goals. "Designing sanctions to make Khamenei relent in his 30-year quest for the bomb is a delusion," they wrote in January for Bloomberg – but "[s]anctions that could contribute to popular unrest and political tumult are not."

Dubowitz and Gerecht are not alone in pushing for US-backed regime change in Iran. Last week, Michael Rubin of the American Enterprise Institute (AEI), who served as Pentagon adviser on Iran and Iraq during the first Bush administration, argued in Commentary magazine that the "key to US national security is simply regime collapse in Iran. How to hasten that collapse should be the guiding principle of US policy."

The administration argues that "crippling" sanctions against Iran have convinced it to resume talks after more than a year of silence, but Tehran's revolutionary government prides itself on resisting western domination and has shown no signs that it will capitulate to P5+1 demands without mutual cooperation. The state news agency IRNA quoted the Iranian president at a rally in April:

"They constantly insult the Iranian nation and use a language of force against Iranians. Speaking on behalf of the Iranian nation, I tell them that this method will not work … and that they should speak with respect."

According to former lead Iranian nuclear negotiator, Seyed Hossein Mousavian, "the language of threat is counterproductive for negotiations"; and "sanctions, covert actions, sabotage and the assassination of Iranian nuclear scientists … have convinced Iran that the US and the west are using the nuclear issue as an instrument for regime change and are not after a realistic solution."

Iranian-American author Hooman Majd points out that it was the P5+1's willingness to talk "without preconditions" – a long-held Iranian demand – that helped restart negotiations. "Iran today feels that if the talks continue as expected – and media reports of US willingness to compromise are correct – they stand much to gain and very little to lose," he said.

Hans Blix, a diplomat and former chief of the International Atomic Energy Agency, says the west needs seriously to consider Iran's cost-benefit calculus and publicize incentives that go beyond sanctions suspension when seeking the suspension of Iran's uranium enrichment:

"If you want results, offers in unemotional language are better than threats and condemnations."

While Iranian and western delegates mostly described recent talks in Istanbul in positive terms, it remains to be seen whether substantial progress can be made ahead of a US-pushed European oil embargo against Iran set for July. For now, talks are set to continue in Baghdad on 23 May.

"The crude view is that the more pressure there is, the more likely that Iran will make concessions," says Pillar. "In fact, the bigger challenge now is not so much getting the Iranians to hurt, but instead, getting them to believe that the west is serious about seeking an agreement."