The tip came in from Israeli intelligence: Iran was preparing to attack U.S. or allied forces in Iraq and Syria. U.S. military commanders’ responded by rushing a flotilla of American warships and bombers to the Persian Gulf — enough firepower to do lasting retaliatory damage.

But the Americans wanted to ensure that Tehran’s leaders knew just what was headed their way. “We wanted that message delivered in the loudest volume possible,” a U.S. defense official told TIME on the condition of anonymity. “The Iranian regime needed to hear it loud and clear.”

The solution? Have John Bolton deliver it.

In a May 5 statement, the National Security Advisor announced that, “Any attack on United States interests or on those of our allies will be met with unrelenting force.” The deployment of the aircraft carrier U.S.S. Abraham Lincoln and bomber jets, Bolton said, was intended “to send a clear and unmistakable message to the Iranian regime.” Said Bolton: “The United States is not seeking war with the Iranian regime, but we are fully prepared to respond to any attack.”

It was a message as subtle as an aircraft carrier, and one that his more staid predecessors might not have been the first pick to deliver.

Traditionally, the national security advisor has worked more behind the scenes, an éminence grise whose influence could often be seen only indirectly. The job has historically been to play an honest broker for the president on the toughest strategic decisions of the day, resolving internal policy disputes and providing a menu of options when needed. But Bolton has taken to it with the flair of the cable TV pundit that he used to be, relishing his ability to keep the America’s adversaries off-balance with aggressive public statements advocating his own stances on the issues.

A conservative insider who joined the White House in April 2018, Bolton has overtly and covertly hijacked the Washington news cycles with his hawkish views. Last June, for instance, he enraged North Korean leadership by suggesting the regime should follow the “Libya model” of nuclear disarmament. Bolton, no advocate of diplomatic détente with Pyongyang, was sure to know that Kim Jong Un wouldn’t want the same fate that befell Libyan dictator Muammar Gaddafi, who was toppled with Western backing and executed less than eight years after agreeing to abandon his nuclear program.

During a January press briefing on Venezuela, Bolton held a notepad on his chest visible to cameras, which said “5,000 troops to Colombia,” presumably in his own handwriting. The message — deliberately exposed or not — pinballed around Washington and provoked speculation about pre-positioning American forces inside Colombia for a rapid deployment in neighboring Venezuela, if called upon.

National security adviser John Bolton during a White House press briefing in Washington, D.C., on Jan. 28, 2019. David Butow—Redux for TIME

Bolton has long advocated toppling Iranian leadership. In 2015, Bolton argued in the New York Times that “only military action” could thwart Iran’s nuclear ambitions. “A strike,” he wrote, “can still succeed.” The White House does not espouse that policy openly.

But regional experts inside and outside the Trump Administration suspect regime change is the ultimate goal of the President’s sweeping economic sanctions on Tehran. Officials in the U.S. intelligence community and the State and Defense departments say they are increasingly worried that Bolton’s escalating “maximum pressure” campaign against Iran is in part an attempt to provoke a military or cyber response from Tehran that would enable the national security advisor to tell a reluctant Trump that a military response, cyber attack, or both was necessary.

Bolton’s announcement Sunday accelerated the deployment of the U.S.S. Abraham Lincoln and adjoining ships and was prompted in part by a series of Israeli warnings, none of which has been confirmed by U.S. intelligence, that Iran has been preparing to strike the U.S. or its allies in the Persian Gulf. Bolton’s Israeli counterpart, Meir Ben Shabbat passed the warnings to Bolton and other U.S. officials two weeks ago. The warnings were first reported on Monday by Israel’s Channel 13 news and were confirmed to TIME by two U.S. officials, one of whom called the Israeli scenario “vague” and lacking specifics about any Iranian planning, weapons or targeting.

The military, however, didn’t need convincing. Gen. Kenneth McKenzie, commander of all U.S. forces in the Middle East, asked for the arrival of the warships to be expedited after seeing the intelligence assessments, the U.S. officials tell TIME. Acting Defense Secretary Patrick Shanahan signed off on the request on Sunday, they say. The ships are now set to arrive from the Mediterranean by the middle of the month, more than a week earlier than planned.

Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, requested the White House issue an announcement — a rare appeal — the officials say. The White House decided the most suitable person to deliver the message was Bolton. “The message needed to come from someone with a strong foreign policy voice,” says Anthony Cordesman, a former intelligence official at the Pentagon who now works at the Center for Strategic and International Studies. “The situation with Iran is becoming increasingly unpredictable. It’s not clear what combination of sanctions and other pressure will result in an aggressive counter-move.”

Even before Trump took office, the U.S. was responding to Iran’s regional expansion with military, intelligence and diplomatic countermeasures. Trump’s decision in May 2018 to walk away from the nuclear deal accelerated the confrontation. And Trump’s campaign for “maximum economic and diplomatic pressure” ratchets up the tension with each additional new sanction that has triggered an exodus of foreign investment and driven oil exports down.

The Administration last month designated the Iranian Revolutionary Guard Corps (IRGC), an arm of the nation’s military, as a terrorist organization, which restricts members’ banking transactions and ability to travel. It marked the first time the U.S. designated an arm of a nation’s government as a terrorist group.

It was a controversial decision. Bolton and Secretary of State Mike Pompeo backed it, but senior military commanders and intelligence officials opposed the move out of fears that Iran would take reciprocal action against U.S. forces. And in a matter of days, the Iranian government declared all U.S. troops in the Middle East terrorists.

The move made a potential target out of each U.S. soldier deployed across the Middle East. Tehran is now involved in every single serious conflict in the region, almost always on the side of America’s enemies.

The U.S. military has thus far avoided direct confrontation with Iranian forces — even when small Iranian boats and drones routinely pestered American naval ships at sea. But Israel and some Gulf nations have pressured the White House to address what they see as a growing Iranian sphere of influence across the Middle East with the IRGC continuing its support for allied militant groups in Iraq, Lebanon and Syria.

Tehran is also said to have increased funding for Shi’ite insurgents opposing American allies in Bahrain, Saudi Arabia and Yemen, U.S. officials say. The nation has also has continued to develop ballistic missile technology in defiance of the United Nations — a topic that Bolton has often highlighted.

“Bolton has been itching for a fight with Iran for years now,” said Ali Vaez, the Iran project director at the International Crisis Group. “He is hoping that U.S. belligerence will push Iran to commit a mistake that could be used as casus belli to bloody Iran’s nose and cut it down to size.”

Write to W.J. Hennigan at william.hennigan@time.com.