The United States has moved a second and third aircraft carrier strike group into the Pacific theater.

The USS Nimitz and USS Theodore Roosevelt have now joined the USS Ronald Reagan in the Seventh Fleet’s western Pacific area of operations. This includes the edgy Korean Peninsula where the Japan-based Reagan has been conducting joint exercises with South Korean forces.

All of which is designed to give North Korean dictator Kim Jung-un second and third thoughts about actually initiating any of the attacks he has so often threatened on U.S. territory or those of its South Korean and Japanese allies. These joint exercises including Japanese ships have been conducted off and on for months now as a show of force, regularly drawing strong denunciations from Pyongyang, which claims to see them as preparation for an invasion.

U.S. super-carrier strike groups are major assemblies of moving military might, as the Navy recruiting ad puts it “100,00 tons of diplomacy.” Besides the nuclear super-carriers, the groups include numerous support vessels, including destroyers and missile cruisers and one or two fleet submarines hanging unseen around the nuclear neighborhood.

The redeployment of the Nimitz from the Middle East, where its planes have been attacking ISIS and al-Qaeda forces, comes as indications mount of new North Korean nuclear weapon and missile tests in the Northern Pacific, most recently over Japan’s northern island of Hokkaido.

The rare assembly of three super-carriers is also a reminder of America’s Pacific presence to China, which is constructing artificial islands with military bases in the South China Sea. State-run media in China have called the U.S. naval presence “a hazard in Asian waters” and “a growing risk to commercial shipping.”

But wait! There’s more. The U.S. naval buildup comes just 10 days before President Trump begins his first Asian trip as commander-in-chief. On Nov. 3, he leaves on an 11-day journey to five Asian countries, including Japan, South Korea and China.

The White House describes the journey as designed to “underscore his commitment to longstanding United States alliances and partnerships, and reaffirm United States leadership in promoting a free and open Indo-Pacific region.”

In South Korea, Trump will meet with President Moon Jae-in, address the National Assembly and meet with both U.S. and Korean troops. There’s been speculation Trump might also visit the DMZ just 30 miles from Seoul.

That’s always a tense place, given past outbursts of violence there and the fact that even 64 years after the Korean War, there is still only an armistice, no treaty.

Such a defiant visit in the face of Kim’s ongoing threats of nuclear attack, however, could give Trump a Reaganesque  “tear down this wall” moment. At the White House Wednesday Trump was asked about such a gesture. He told media they would be “surprised” by what he planned.