HMM: To China, America Finally Looks Vulnerable.

When Chinese leaders gaze out toward the Pacific, their panorama is obstructed by a string of military airfields, naval anchorages, radar emplacements and listening posts sentineled by U.S. forces and their allies.

Breaking through what they regard as a hostile chain of containment is a national priority.

To do so Beijing must weaken the U.S. alliance network. Can Washington hold the line?

That’s the larger question hanging over the all-out struggle that Beijing is waging to prevent the installation of a U.S. antimissile battery in South Korea, meant to protect against a North Korean nuclear attack, which took a dramatic turn last week with the removal from office of South Korean President Park Gyeun-hye.

Pyongyang may well produce Donald Trump’s first international crisis. Its nuclear menace, along with missile defense, will be high on the agenda when he holds his first meeting with his Chinese counterpart, Xi Jinping, tentatively scheduled for April in Mr. Trump’s private club in Florida, Mar-a-Lago, according to Chinese officials.

Barack Obama infuriated Beijing with his military-flavored “pivot” to Asia. To the Chinese leadership it was yet more Cold War-style gamesmanship, and to test U.S. resolve they pushed back with bullying tactics against U.S. friends and allies, for instance sending a giant oil-drilling rig into waters off Vietnam protected by a flotilla of paramilitary vessels.

Obama’s Asia pivot was a dangerously empty gesture — enraging Beijing with his intentions but without enough credible force for them to fear his capabilities.

Now comes the tense part as Beijing, in part via North Korea, tests the new Administration and our longstanding alliances with China’s neighbors.