If the Trump administration can strengthen U.S. relations with Thailand, Vietnam, and the Philippines, we need not be terribly concerned over China's new naval base in Cambodia.

As the Wall Street Journal reports, China is preparing to use a deep water port at Ream, Cambodia. That port would enable the Chinese navy to surge warships against the southern flank of U.S. forces in the event of a conflict over the South China Sea. It would also allow China to threaten critical global trade flows through the Singapore entrance to the Malacca Strait.

It's a real threat, but one that can be constrained by the reinforcement of U.S. alliances. Geography explains why.

My annotated map below shows the three current major commands of the Chinese navy, identified with red stars. Starting at the top with the Northern Theater Navy at Qingdao, we go south to the Eastern Theater Navy at Ningbo, then down to the Southern Theater Navy at Zhanjiang. The southernmost red star is Ream, Cambodia.

In the event of conflict, the Chinese would surge forces from these three commands in an attempt to prevent the U.S. military from accessing the South China Sea. With dozens of surface warships and 36 attack submarines between Ningbo and Zhanjiang, this is no small threat. To challenge this Chinese control strategy, the U.S. would have to deploy attack submarines into the South China Sea through the Taiwan-Philippines gap and from waters west of the Philippines (the two arrows at right). The U.S. would also rely on long-range bomber, missile, and, eventually, artillery strikes.

(Google Maps with Tom Rogan annotations)

But here's where Ream comes into the picture.

Because if China can surge forces from Ream, they will be able to challenge U.S. strongholds (identified by the blue circles) from both the South and North. These strongholds are where U.S. carrier strike groups might attempt to operate in harassing the southern flank of Chinese forces.

The problem: Ream would allow the Chinese to match their ballistic missile threat to U.S. carriers with a potent surface and submarine threat. This is the threat the U.S. must address.

That brings us back to the allies. Because if the U.S. can consolidate greater offensive support from the Philippines and Vietnam, it could encircle and suffocate the Chinese military in the South China Sea. There are indications that both nations would be receptive to these efforts. As with other U.S. allies, they recognize China's increasingly overt aggression and see America as a necessary friend.

What about Thailand? Just northwest of Ream is the U-Tapao Royal Thai Navy Airfield. A critical base for the U.S. military during the Vietnam War, the base has new relevance in the context of Chinese operations at Ream. Put simply, it would allow the U.S. Air Force to annihilate Ream in the event of any conflict. Of course, the Thais would have to approve this offensive opportunity.

Fortunately, most Thais and their military are reflexively pro-American. Thailand's tentative movement back to civilian government, as resulting from the March 2019 parliamentary elections, should also allow the U.S. to more openly support renewed investment and closer diplomatic relations with Bangkok. A Trump administration priority should thus be to establish preferential trading relationships with Thailand in return for greater U.S. military access.

If we do these things, China's base at Ream will offer its forces little new strategic advantage. China will remain a potent threat, but not a greatly strengthened one. If war with China one day comes, as is sadly likely, America will have a good chance of victory.