KANDAL, Cambodia — Cambodia’s long-running prime minister, Hun Sen, cut a red ribbon today on a symbol of Communist China’s rising clout here, a 33-mile section of Phnom Penh’s new Ring Road. 

Financed by the Export-Import Bank of China and built by the Shanghai Construction Group, the gleaming, four-lane divided highway came wrapped in Chinese professions of solidarity with Cambodia, its closest ally in Southeast Asia. 

China’s news agency, Xinhua, quoted a 41-year-old resident, Saing Sokchea, as saying: “China is the best partner of Cambodia, helping us develop bridges, roads and other infrastructure.”

The new Ring Road segment represents just a teacup of the river of money that China is pouring into Cambodia’s highways, airports, and railroads. 

Southeast Asia’s top beneficiary of China’s Belt and Road Initiative, Cambodia is conveniently sandwiched between two China skeptics — Vietnam and Thailand. 

Over the last decade, substantial Chinese investment contributed to the doubling of Cambodia’s economy, bringing the nation of 17 million people closer to the levels of its neighboring giants. 

Riding this economic boom, Mr. Hun announced today that on Monday he will submit the name of his oldest son, 45-year-old Hun Manet, to King Norodom Sihamoni for approval as prime minister.

Near here, at a new Ring Road interchange, Hun Sen Boulevard leads to a 10-square-mile construction site. There, bulldozers of the China Construction Third Engineering Bureau Group push through a landscape of rice paddies, building what is to rank, by size, the ninth-largest airport in the world. 

At buildout in 2050, Phnom Penh’s future international airport is to rival the airports of Bangkok and Saigon, handling the world’s largest jets and 50 million passengers annually. This time next year, Techo Takhmao International Airport is to open with the first of three 2.5-mile-long cement runways.

This year, Cambodia is to receive only 2 million visitors by air, about a quarter of the pre-Covid peak, in 2019. Yet tourism planners believe that Cambodia will soon return to the boom years when jets flew here from 20 Chinese cities. 

Although Cambodia is at the centerpiece of a region historically known as Indochina, there are no flights to Cambodia from India.

In October, a Chinese construction company plans to deliver Siem Reap-Angkor International Airport, the gateway to Cambodia’s premier tourist destination, the 12th century temple complex of Angkor Wat.  

Designed to initially handle 7 million passengers a year, this airport will be Cambodia’s largest until Phnom Penh’s new airport opens here.

Angkor is to be operated for the next 50 years by a consortium of companies from China’s southern Yunnan Province, which borders Vietnam, Laos, and Myanmar. Last year, China inaugurated a 642-mile railroad to Laos from Kunming, capital of Yunnan. 

In Cambodia, officials are talking with Chinese counterparts about extending this railroad south to Cambodia’s coast on the Gulf of Thailand.

More immediately, Chinese companies plan to fulfill a century-old French colonial dream of building an east-west railroad between Saigon and Bangkok. 

In February, the elder Mr. Hun traveled to Beijing to further talks about a $4 billion rebuild of 237-mile, formerly French rail line to the Thai border from Phnom Penh. To the east, an entirely new line would cross the Mekong River and connect with Vietnam’s rail network.

Also on land, Chinese companies are converting into expressways a national road system first built during the time of the French protectorate, which ended in 1953. 

Last October, a Chinese company inaugurated Cambodia’s first expressway — a 116-mile, $2 billion divided highway that links Phnom Penh’s Ring Road with Sihanoukville, the country’s main seaport. 

With a 75-mile-an-hour speed limit, the four-lane highway cuts in half the drive time between the capital and the coast — to 90-minutes.

Built on a build-operate-transfer system, the toll road seems too rich for Cambodian palates. Charging $12 for the drive, China Road and Bridge Corporation has a 50-year concession for what is now an empty highway.

Undeterred, Mr. Hun broke ground in June with China’s ambassador to Cambodia, Wang Wentian, for the construction of Cambodia’s second toll road — an 84-mile, $1.4 billion expressway running between Phnom Penh and the Vietnamese border to the east. 

At the ceremony, Mr. Hun announced that the Chinese company is studying $4 billion worth of new expressways linking the capital with the Thai border to the west, and to Siem Reap in the north.

The western expressway would pass Phnom Penh’s spanking-new 75,000-seat, Chinese-built arena, Morodok Techo National Stadium. The largest in the nation, the stadium is shaped like a ship with two 325-foot-tall “prows” at either end. 

Evoking ships used by China’s 15th century Admiral  Zheng He, the architects sought to recall the centuries of contact between China and Cambodia.

The stadium was inaugurated in May, in time for Cambodia to host the 32nd Southeast Asian Games, the first time it hosted the games for 11 nations of the region. 

Keeping the lights on was the Chinese-built 400 MW Lower Sesan Dam, Cambodia’s largest hydroelectric power project.

Nationally televised, the games’ hoopla — music, dance, lighting displays, and fireworks — contributed to popular good feelings in the runup to the government’s stage-managed general elections of July 27. 

With serious opposition parties and independent media closed, the ruling Cambodian People’s Party won all but five seats in the 125-member lower house.

Among the winners was the prime minister’s son and named successor, Hun Manet. Although educated at West Point and at New York University, the younger Mr. Hun has not cultivated contacts in Washington. 

In contrast, as part of preparation for taking over command of Cambodia, he traveled with his father to Beijing to meet with China’s top leader, Xi Jinping. 

Shortly after Hun Sen announced that his son would succeed him, he wrote his Chinese counterpart, Li Qiang, assuring him that “the new government’s policy toward China based on mutual traditional friendship, trust, and win-win cooperation will not be changed.”

The job of persuading Americans that Cambodia is not becoming a Chinese satellite falls to the nation’s power couple in America — Cambodia’s ambassador to America, Keo Chhea, and his wife, Sophea Eat, who is Cambodia’s ambassador to the UN. In June, they gave a joint interview to Politico.

“U.S. politicians understand that we aren’t on the Chinese side,” Mr. Keo said. “We are not pro-Chinese per se — as the media in the U.S. says — but we need to survive.”

His wife added that “we are trying to be friends with everyone.” She noted that “Cambodia is seen as a Chinese client state. But it’s just a small boat trying to maneuver in a sea of many big ships.”