The foreign ministers of Iran and the P-6—the five permanent members of the UN Security Council, plus Germany—agreed late Tuesday to extend their talks on the political framework for an agreement to “normalize” Iran’s civilian nuclear program for one further day.

The US had long insisted that the framework needed to be finalized by the end of Tuesday, March 31 to forestall a US congressional push for the imposition of still more punishing economic sanctions on Iran.

US Secretary of State John Kerry reportedly threatened early Tuesday evening to walk away from the talks, which are being held in Lausanne, Switzerland. But, ultimately, the US and its European Union allies said sufficient progress had been made to justify extending the negotiations into Wednesday.

While emphasizing that “difficult issues” remain, US State Department spokesperson Marie Harf said, “We’ve made enough progress in the last days to merit staying until Wednesday.”

A member of the German delegation at the talks told Reuters late Tuesday that the negotiations had been “very tough.” He added, “Whether it will succeed remains open.”

White House spokesman Josh Earnest threatened that the entire negotiations could be scrapped if the impasse was not soon overcome. “We’re not going to wait…until June 30 to walk away,” said Earnest, in reference to the date when the current interim agreement between Iran and the P-6 expires and the two sides are supposed to have finalized all elements of a permanent agreement.

Earnest did not explain what the US would do if it scrapped the negotiations with Iran. But both President Obama and Kerry have repeatedly said that the alternative to a diplomatic solution is a path that begins with the adoption of legislation pending before Congress that targets the complete shut-off of all Iranian oil exports and ends in all-out war. 

In an effort to put further pressure on Iran, French Foreign Minister Laurent Fabius has reportedly vowed to leave the Lausanne talks at daybreak Wednesday. In recent weeks, the French, who view their ties to Saudi Arabia and the other oil-rich sheikdoms as pivotal to their economy and military-geopolitical strategy, have publicly clashed with the Obama administration over the Iran talks.

The French have been demanding even greater restrictions on Iran’s civilian nuclear research program and have objected to Washington’s March 31 deadline, saying the push for an early framework agreement could result in unnecessary concessions being made to Tehran. “We want a deal. They need a deal. The tactics and the results of the negotiations should reflect this asymmetry,” recently tweeted Géraud Araud, France’s ambassador to the United States.

US and other Western officials have been suggesting for several days that any agreement that does emerge from the Lausanne talks will be short, a scant two to three pages, and that while it will include some important specifics—such as the number of centrifuges Iran will be allowed to continue running—others will likely be omitted. One Western diplomat was quoted by Reuters as saying that the agreement would be “incomplete and kick some issues down the road.”

Iran has already made sweeping concessions. These include accepting that Iran’s nuclear program should be subject to a special set of constraints for fifteen years; keeping less than a third of its centrifuges in operation; submitting its nuclear program to far and away the most intensive ever International Atomic Energy Agency inspection regime; and permanently scaling back its nuclear facilities.

The framework talks have reportedly stalled over two issues: the extent to which Iran will be free to pursue civilian nuclear research, particularly the perfecting of a more advanced type of centrifuge in the agreement’s 11th to 15th years, and when and how UN sanctions will be lifted.

Iranian officials have indicated that the sanctions question is the make-or-break issue. “There will be no agreement if the sanctions issue cannot be resolved,” Iranian negotiator Majid Takhteravanchi told Iran’s Fars news agency. “This issue is very important for us.”

The US and its allies are determined to keep Iran under UN sanctions for years to come. The most to which they reportedly will agree is their suspension. Moreover, they are pressing for language that would make the re-imposition of sanctions effectively automatic, should Washington declare that Tehran is not fulfilling its end of the bargain.

Russia has reportedly joined Iran in opposing an automatic “snap-back” of sanctions, arguing in favor of a process where a further UN Security Council resolution, subject to Moscow’s veto, would be required.

Under the sanctions the US and its European Union allies imposed beginning in 2011, Iran’s oil exports have been halved and it has been frozen out of the world banking system, losing access to close to $100 billion in central bank reserves and oil-sale proceeds.

Compared to this, the UN sanctions, which ban the export of arms and nuclear-related technology to Iran, as well as freezing the assets of certain companies and individuals associated with Iran’s Revolutionary Guards and nuclear program, are little more than a troublesome inconvenience.

Nevertheless, Washington views the UN sanctions as vital in providing international legitimacy for its campaign to bully Iran and key to upholding the punishing US-EU sanctions.

Washington’s ostensible goal in the nuclear talks is to establish a mechanism whereby the “peaceful” purpose of Iran’s nuclear program can be tested to the satisfaction of the “international community.”

Its real and overriding objective is to strengthen US strategic dominance over one of the world’s most important oil-exporting regimes and force the Iranian bourgeoisie to abandon any challenge to US strategic interests.

This finds expression in the mechanism it is seeking to build into the nuclear deal with Iran. Tehran is to be treated as an outlaw regime that has to prove its bona fides to the US by meeting tests designed by Washington, with the US and its allies acting as the judges of whether the requirements have been met.

Insofar as Tehran is deemed to meet these tests, it will be rewarded with a gradual “relaxation” of the sanctions, stretching years into the future. But should Washington decide that Iran is not sufficiently compliant, it can fabricate a crisis over an ostensible Iranian transgression, resume the sanctions, and reactivate the Pentagon’s plans for a regime-change war against Tehran.