When President Donald Trump pulled the United States out of the 2015 nuclear deal with Iran last year, he drew the U.S. back into an antagonistic posture from which it had taken years to step out. On Sunday, his national security adviser, John Bolton, increased tensions even further, when he announced that the U.S. “is deploying the USS Abraham Lincoln Carrier Strike Group and a bomber task force to the U.S. Central Command region to send a clear and unmistakable message to the Iranian regime.”

Bolton, who has a long record of being hawkish on Iran, said the move was in response to “a number of troubling and escalatory indications and warnings.” He offered no specifics about what those indications or warnings might be. He added that while the U.S. “is not seeking war,” it wants to show it is “fully prepared to respond to the attack.”

It’s possible that this was a response to a perceived threat — real or imagined — to U.S. troops in places like Iraq, where Iranian-backed Shia militias hold sway. And that has grown ever more likely, said Richard Nephew, senior research scholar at the Center on Global Energy Policy, as, “The policy choices of this administration have escalated things with the Iranians.”

But, he said, the presence of these ships has long been part of U.S. strategy, be it for support for missions in Iraq or counter-piracy operations, and the USS Abraham Lincoln was going there anyway.

“What I find disturbing is that this is now being postured [by Bolton] as something that’s an extraordinary step, with the very clear implication that we are preparing to use force to respond to the Iranians,” said Nephew, who is the former Director for Iran on the National Security Staff under President Barack Obama.

In other words, Bolton’s statement is what stands out to experts — not the deployment of the carrier.

“The statement is a bit unusual, but I see it as more of a symbolic move — not unlike Gen. [Michael] Flynn putting Iran on notice in 2017,” said Ariane Tabatabai, associate political scientist at the RAND Corporation. “Of course, we can’t discount the possibility of escalation but I don’t think either Iran or the U.S. want to go there,” she added, answering questions via e-mail.

The point of this vintage move, is to maintain the “maximum pressure strategy designed to raise the costs of Iranian foreign policy enough to make the regime stop what it’s doing either by provoking a change in calculus or by leading to its collapse,” said Tabatabai.

Iran, said Nephew, is unlikely to “take a swing” at U.S. targets in a direct, overt way. Providing support for their proxies to do so is a “fairly big constant with respect to the U.S. and Iran, in the region.”

But he’s troubled by the decision to publicly link the deployment of U.S. forces with an intention to respond to Iran militarily, as it “raises the stakes for everybody.”

In addition to potentially forcing Iran into a position where it feels compelled to demonstrate its own resolve, it will also complicate U.S. operations with countries like Oman and Iraq, who aren’t anxious to get drawn into a conflict with Iran.

Bolton’s policy time machine

This is also not the first time the U.S. has tried to manifest a military threat at Iran’s door — actually, it’s a very Vice-President-Dick-Cheney-circa-2007 move. Cheney, however, made his statement while on deck of the USS John C. Stennis on May 11 of that year.

“We’ll disrupt attacks on our own forces. We’ll continue bringing relief to those who suffer, and delivering justice to the enemies of freedom. And we’ll stand with others to prevent Iran from gaining nuclear weapons and dominating this region,” said the vice president, behind him, five F-18 Super Hornet warplanes.

But Iran didn’t get nuclear weapons. Instead, President Barack Obama entered into an agreement with Iran, along with China, Russia, France, the United Kingdom, and Germany, that saw Iran limit enrichment materials in exchange for sanctions change.

Verified by strict and regular U.N. inspections, Iran has abided by the terms of that deal, despite President Trump pulling the U.S. out, violating the deal (the Joint Comprehensive Plan of Action, or JCPOA) and reimposing sanctions.

The return of those sanctions on Iran has illicited an angry response, with the country’s Revolutionary Guard (or IRGC — which the Trump administration declare a terrorist organization in April) threatening to close the Strait of Hormuz, a key route for roughly 40 percent of global oil shipments.

Iran made a similar threat in 2011, but never ended up acting on it. Much like President Trump’s threat to shut down the U.S. border with Mexico, closing the Strait of Hormuz is difficult, if not impossible, to pull off.

To start with, while Iran possesses the longest shoreline in the strait, it does not control the entire strait, and would need cooperation from Oman. In addition, Iran would risk the ire of countries it sees as allies, such as China and South Korea, as their oil purchases also travel through the strait.

Iran to test limits of nuclear deal

Even if Iran can’t shut down the Strait of Hormuz or launch a direct attack on the U.S., that doesn’t mean Iran isn’t considering other options in retaliation: News out of Iran indicates that the government might — as soon as Wednesday — announce steps that might, said Tabatabai “test out the limits of the JCPOA” via steps it will be taking within the framework of that agreement, intended to increase pressure on European partners still in the deal.

It’s unclear what those steps might be — it could be somehow stepping up nuclear activities while staying within the confines of the agreement, or other moves.

Nephew, who worked on the JCPOA, told ThinkProgress the agreement doesn’t have a lot of loopholes, but within the confines of the agreement, Iran can do things like expand their production of heavy water, do some work on advanced centrifuges, or pursue research and development in related, though non-prescribed activities.

They can do this without violating the terms of the JCPOA, but pushing back against the interpretation of key definitions and limits.

“They can change their interpretation of those limits…and if you are the Iranians, that’s where you start off…and you basically tell the Europeans, ‘Listen, we were prepared to interpret things differently back when there was a reasonable exception for us getting some economic relief. Now that we don’t, this is our interpretation, Deal with it,'” said Nephew.