• Trying to save the Iran nuclear deal is a "stunning mistake" by the Biden administration, John Bolton said.
• Last year, signatories of the original pact began the first of what would become many rounds of negotiations in Vienna to revive the deal since the U.S. withdrew from it in 2018 under the Trump administration.
• In the 2015 agreement, Iran would have dismantled much of its nuclear program and allowed more international inspections in exchange for economic sanctions relief.

Former President Donald Trump's national security advisor, John Bolton, said the Biden administration is making a "stunning mistake" in trying to return to a nuclear deal with Iran.

Bolton, a longtime Iran hawk, argued the deal would make Iran a "better partner" for Russia and pose a threat to not just the Middle East region, but also the world.

"I think the immediate consequence, obviously, will be the unfreezing of billions of dollars of Iranian assets, which will go back under their control, with their discretion to spend it on their nuclear program, their support for international terrorism in the Middle East and beyond," Bolton told CNBC's Dan Murphy. "It's really a stunning mistake by the Biden administration."

The U.S. National Security Council, reached by CNBC for comment, refuted Bolton, saying Iran would not get sanctions relief without "comprehensive" inspections.

Should the original 2015 deal come back, "Iran would receive no sanctions relief at all absent its imposing significant and verifiable restraints on its nuclear program and returning to the most comprehensive inspections [the] regime ever negotiated," said a National Security Council spokesperson, Becky Farmer.

The resurrection of the deal hinges on a sticking point — a long-running investigation by the International Atomic Energy Agency (IAEA) into traces of uranium at three of Iran's undeclared nuclear sites years ago. Tehran wants the investigative probe shut down, something the agency and Western governments oppose.

Farmer added that the IAEA has "very little visibility" into Iran's program. "This is thanks to the previous Administration's reckless decision to leave a deal that was working," she said in an email.

Trump killed deal in 2018

Last year, signatories of the original deal began the first of what would become many rounds of negotiations in Vienna to revive the agreement. The Trump administration withdrew from the deal in 2018.

Under the 2015 agreement, formally known as the Joint Comprehensive Plan of Action or JCPOA, Iran would have dismantled much of its nuclear program and allowed more international inspections in exchange for economic sanctions relief.

Iran, which was the fifth-largest oil producer among OPEC members in 2020 may raise additional crude supplies upon the materialization of a deal, according to some analysts. That would offer some relief to a strained global energy market.

However, Bolton argued that increasing North American crude output would have a greater impact compared with a potential rise in Iranian oil production from a revived nuclear deal.

A closer Iran-Russia relationship?

Bolton warned that lifting sanctions could lead to Iran establishing closer ties with Russia.

"I think it just stands to reason that relieved from international sanctions, a richer, stronger Iran will grow closer to Russia. … By helping free Iran from the economic sanctions, it makes it a better partner for Russia."

Bolton noted that Russia and China have an existing "entente" and that a three-way partnership between Russia, China and Iran would have global implications.

"China's providing economic aid directly and indirectly to the Russians, in their concern about the sanctions over Ukraine. I think China would expect Russia to do the same if it decided to go after Taiwan," said the former U.S. national security advisor.

The Chinese Embassy in Singapore did not immediately respond to a request for comment.

"In the Middle East, where they have overlapping interests, their preferred partner is Iran. So it's a kind of three-way arrangement that I do think has global implications."

Fear in Gulf, Israel

Bolton also contended that an Iran deal would harm key U.S. allies in the Middle East.

"The allies of the United States that are most worried about Iran are … the Gulf Arab states and Israel," he said. "And those are the countries that, I'm afraid, the U.S. is selling out here by not taking into account the Iranian regime's ultimate objectives to get hegemony across the Middle East."

In June, the White House emphasized it is determined to make sure Iran does not acquire a nuclear weapon.

"We think a diplomatic agreement is the best way to do that. We think a mutual return to the JCPOA is in the interest of the United States and our partners," current national security advisor Jake Sullivan told reporters. "And there is a deal available on the table to Iran, and it's up to Iran to decide whether or not it wants to take it."

Bolton's comments come on the heels of escalated protests in Iraq on Tuesday, after powerful Shiite Muslim cleric Muqtada al-Sadr announced his resignation from politics.

"What's going on now in Baghdad should strengthen our resolve not to go back into the Iran nuclear deal, not to do anything that empowers the regime in Tehran but work together with our Arab friends and our Israeli friends to try and counter this menace, which is the real source of the instability we see in Baghdad."