Secretary of state will brief Senate banking committee as administration tries to avoid torpedoing nuclear talks

All eyes are on John Kerry and his attempt to persuade a markedly skeptical Congress to forestall a new wave of sanctions on Iran, as the international community hopes to close out a nuclear deal in eight days' time.

The secretary of state, who on Tuesday was returning to Washington empty-handed after talks in Geneva over Iran’s nuclear program failed to yield an interim deal, will meet this week with lawmakers who believe enacting additional economic sanctions will give the US increased leverage when negotiations resume on 20 November.

The Senate banking committee, which Kerry is slated to brief in private on Wednesday, is considering a new sanctions push that has bipartisan support. The panel has agreed to delay pushing its sanctions bill out to the full Senate – after already delaying it for the Geneva talks – until Kerry makes his case, giving the former Massachusetts senator a limited window in which to forestall the new sanctions.

Vice-president Joe Biden, the administration’s closer on many aspects of legislative dealmaking, is expected to engage with lawmakers as well.

Additionally, senator Bob Corker, the ranking Republican on the Senate foreign relations committee, has for now stopped short of endorsing a new wave of sanctions. The pressure is on Kerry, Corker implied, to convince a skeptical Senate that additional sanctions ought to be avoided.

“This week, sitting down, talking with secretary Kerry is going to be an important element of what we do,” Corker told NBC’s Meet the Press on Sunday.

Sanctions pressure, promoted by the White House and eagerly approved by a Congress hostile to Iran, is a double-edged sword for the Obama administration. The administration credits the sanctions with compelling Iran to negotiate – “They’re anxious to reach an agreement in the sense that their sanctions are very, very difficult,” Kerry told the BBC on Monday – but fears that additional sanctions pressure during negotiations will convince Iran that talks are pointless, leaving the world with an unpalatable choice between a nuclear Iran and a new Middle East war.

Jen Psaki, the State Department spokeswoman, told reporters on Tuesday that additional sanctions now would be a “mistake”.

“There’s a real danger, and most Iran analysts agree with this, that introducing new sanctions in the current climate would basically enable hardliners in Iran to make the argument that their willingness to be more conciliatory has been pocketed by the United States and rewarded simply with more pressure, and it would basically undermine the argument for moving forward for diplomacy,” said Colin Kahl, until recently the Pentagon’s top Iran policy official.

But Kahl said more sanctions might be reasonable if there is no deal by the end of the year and Iran continues apace with nuclear activity. “I think the administration would support increasing sanctions from that point forward,” Kahl told a conference call arranged by the Wilson Center.

Accounts continue to differ about what got in the way of the Geneva deal. Early reports indicated that the French took a harder line than their western negotiating partners. Kerry, seeking to narrow differences within the western coalition, has suggested that Iranian diplomats needed to return to Teheran for clearer guidance on their ability to agree to western terms.

But major sticking points, particularly on Capitol Hill and in Israel, are Iran’s ability to continue enrichment activity, which it claims as a national right under the international Non-Proliferation Treaty (NPT); the continued construction of a heavy water nuclear reactor at Arak; and the scope of what the administration insists will be a partial and reversible lifting of sanctions.

Kahl floated a scenario whereby the west and Iran might be able to agree on language for an interim deal.

“Even if there’s not an explicit right under the NPT, US policy also seems to recognize that it is possible to be compliant with the NPT and enrich on one’s soil, and I think this is basically the way out,” Kahl said.

Acknowledging the “fact of limited domestic enrichment in Iran under extraordinary constraints, safeguards, inspections and verification procedures, etc” might be palatable to the US, Kahl said, “and if the Iranians want to interpret that agreement as respecting their quote-unquote 'rights', so be it, and that basically allows a face-saving way out for both sides.”

Whether that can satisfy Congress is an open formulation. Israel, a critical US ally, has denounced a deal with Iran even before one exists. Amos Yadlin, a retired two-star Israeli general, said there was a “deficit of trust” between Washington and Jerusalem on Iran.

At the White House on Tuesday, spokesman Jay Carney portrayed war as a likely alternative to a deal with Iran – seemingly a warning to recalcitrant lawmakers.

“The American people do not want a march to war,” Carney said.