It's the White House's favorite term when it comes to discussing the Iran nuclear deal. If things don't work out after long-time economic sanctions on Iran are lifted, they can be "snapped back" into place.

A Tuesday deadline looms for Iran to work out a final deal with the so-called P5 plus one countries (the United States, France, the United Kingdom, Russia, China and Germany) that would allow Tehran to pursue a peaceful nuclear programme and end sanctions on them.

The White House has already indicated that deadline will likely be extended. Still, a key selling point for US President Barack Obama has been the ability to "snap back" sanctions should Iran break any future deal.

"The prospect of those sanctions snapping back into place," White House Press Secretary Josh Earnest told reporters on Monday, “does serve as a significant financial disincentive for the Iranian government to violate some of the commitments that they have already made.”

But one longtime White House journalist snapped back at Earnest, saying that using the term and trying to get people to believe it is, "right up there with belief in the tooth fairy".

It's a deliberate and misleading term, according to some analysts. "It took about six years to put in place the massive international sanction regime Iran is under," said Alex Vatanka from the Middle East Institute in Washington, DC. "President Obama's point on 'snapback' is easier said than done."

The Russians apparently agree. Back in May, Vitaly Churkin, Russian Ambassador to the United Nations, told Bloomberg News that snapping sanctions back into place was not guaranteed.

Rich Galen, a Republican strategist and longtime Washington consultant, said, it's a marketing ploy by the White House to reassure Americans that their adversary is ready to reform.

According to Galen, the message is quite simply this: "'No worries. We're [the US] in control of the process,' which couldn't be farther from the truth."

DC Dispatches reached out to the White House for clarification on what a "snap back" period would look like. "Nothing is finalised yet," said Ned Price from the National Security Council. "And, as we have long said, nothing is agreed until everything is agreed."