On Thursday, the U.S. Pacific Fleet held a change of command ceremony at Pearl Harbor’s Kilo Pier as Adm. Samuel Paparo handed command to Adm. Steve Koehler.

Koehler came to Hawaii after a stint at the Pentagon as the director for strategy, plans and policy of the Joint Chiefs of Staff since 2022. But he’s no stranger to the Pacific, having commanded the 3rd Fleet in San Diego as well as serving as deputy commander to the Pacific Fleet and director of operations for U.S. Indo-Pacific Command in Hawaii.

“He knows the area, he knows the region, he knows the people,” current INDO­PACOM commander Adm. John Aquilino told attendees at the ceremony. “He has those relationships, and he knows the threat … (and) it’s getting more dangerous, not less.”

The Pacific Fleet commander heads all U.S. naval forces in the Pacific and parts of the Indian Ocean, including the Navy’s 3rd Fleet and the Japan-based 7th Fleet. It’s the world’s largest military fleet, which Paparo had led since May 2021 after taking over from Aquilino.

Historically, the commander of the Pacific Fleet often takes over INDOPACOM — which oversees all U.S. military forces in the region. Since its formation in 1947, it has always been commanded by a Navy admiral. Paparo was recently confirmed by the U.S. Senate to succeed Aquilino, who is scheduled to retire next month.

In the interim, Paparo will take time off to spend time with his family, according to Pacific Fleet officials.

The Navy’s top officer, Adm. Lisa Franchetti, flew in from Washington, D.C., for the ceremony and awarded the Distinguished Service Medal to Paparo. In her remarks, she said Paparo “personally pushed us to think, act and operate differently.”

The transfer of commands takes place at a time of high tension in the Pacific — which the Pentagon considers to be the military’s top priority theater of operations. Across the region, several potential geopolitical flashpoints loom large as rival militaries face off and test missiles frequently fly.

“Our system that prized economic development is shifting to an emphasis on security. And our system that relies on market efficiencies has moved towards building national resiliency,” said Paparo. “We see through all of these shifts, most significantly here in the Indo-Pacific, a revisionist, revanchist and expansionist PRC (People’s Republic of China); a ruthless Russia; and (an) intractable North Korea, and violent extremist supporters who believe in the logic of power … in this contested environment, deterring conflict is our highest duty.”

Tensions have simmered particularly in the South China Sea, a critical waterway that more than a third of all international trade travels through. Beijing claims nearly the entire region as its exclusive sovereign territory. Chinese forces have built bases on disputed reefs and atolls to assert those claims and have occasionally attacked fishermen and other maritime workers from neighboring countries.

Tensions have lately broken into clashes around the Philippines, where ships from the Chinese and Philippines coast guards have frequently fired water cannons at and rammed each other in disputed territories. A 2016 international court ruling in favor of the Philippines found that China’s claims had “no legal basis,” but the Chinese military has doubled down and accused the Philippines of “provocation,” and the U.S. of interfering.

But arguably the U.S. military’s biggest worry in the region is Taiwan, a major trade partner for the U.S. and a key provider of semiconductors that many American companies depend on to make their products work. The Taiwan Strait, between the island and mainland China, is one of the busiest shipping lanes in the world. Beijing considers self-ruled Taiwan a rogue province, and Chinese leader Xi Jinping has vowed to bring it under its control by military force if necessary.

Taiwan’s Navy chief, Adm. Tang Hua, attended the ceremony Thursday at Pearl Harbor as part of a visit to the United States this week.

Officially, the United States has not diplomatically recognized Taiwan since normalizing relations with China in 1979, but the Taiwan Relations Act of 1979 maintained de facto ties and requires the U.S. to provide Taiwan with weapons “of a defensive nature” and “resist any resort to force or other forms of coercion that would jeopardize the security, or the social or economic system, of the people on Taiwan.”

Last month, Aquilino testified in front of the Senate Armed Services Committee that “all indications point to” the Chinese military being ready to invade Taiwan by 2027, telling lawmakers “my assessment is they are actually spending more on defense than they articulate,” and adding later that “we haven’t faced a threat like this since World War II.”

In his remarks after taking command, Koehler said, “Our competitors continue to challenge the rules-based order with all the instruments of their national power in their quest for might to make right and in the pursuit of the future in which the strong do what they can and the weak suffer what they must.”

Amid tensions, President Joe Biden and diplomats have sought to lower the temperature and pursue direct talks with China. During a webinar hosted last month by the East-West Center in Manoa, U.S. ambassador to China Nicholas Burns, expressed cautious optimism about the state of relations between the two countries, saying, “I think 2023, especially the second half of 2023, led to a relatively more stable relationship between our government in the United States and the government of the People’s Republic of China.”

In October, a bipartisan U.S. congressional delegation visited China for the first time in four years, and in November, Biden met face to face with Xi during the 2023 Asia-Pacific Economic Cooperation summit in San Francisco. On Tuesday, the two leaders spoke by phone for nearly two hours, and Secretary of State Antony Blinken is set to visit China in the coming weeks.

“We believe that there is no substitute for regular communication at the leader level to effectively manage this complex and often tense bilateral relationship,” National Security Council spokesperson John Kirby told reporters after the Tuesday call.

In Hawaii, Koehler takes command at a time when the Navy is working to rebuild trust with island residents after the 2021 fuel spill from the Navy’s Red Hill bulk fuel storage facility tainted the Navy’s Oahu water system, which serves 93,000 people. The facility sits just 100 feet above a critical aquifer that most of Honolulu relies on for drinking water.

Last month, Joint Task Force Red Hill, a military organization that was tasked with removing more than 104 million gallons of fuel from the facility, formally completed its mission. But the long-term closure and remediation of Red Hill — which will be overseen by a new Navy task force — is expected to take considerably longer.

Paparo took command of the Pacific Fleet the same day as the May 4, 2021, spill, which made its way into the facility’s fire system, which was ruptured in November 2021 and leaked fuel into the Red Hill water well. After the November incident, Paparo ordered an investigation.

Last year, attorneys representing families sickened by the water crisis, in a civil lawsuit against the U.S. government, attempted to depose Paparo, but a federal judge ruled that the attorneys had not demonstrated Paparo had information they couldn’t get elsewhere and did not have a compelling reason to force his testimony.

Koehler told attendees at the ceremony that he and his family “are fired up to be back here in Hawaii. Truly, really ecstatic. As we hopped off the airplane a week and a half ago, it felt truly like coming home … I’m excited to rejoin the ohana here and meet the challenges.”