The Navy is planning to forward-deploy another three-ship “amphibious ready group” in the Pacific — a move that will add to highly prized ship-to-shore capability in the maritime-dominated region as well as bring more than 4,400 sailors and Marines and millions of dollars in economic impact to the chosen destination.

U.S. Sen. Mazie Hirono thinks it should be in Hawaii.

“Strategic location, existing infrastructure and access to training sites are all factors that make Hawaii a strong candidate to host the (amphibious ready group/Marine expeditionary unit),” Hirono said in an email. “While this decision is ultimately made by the Department of Defense, I support shifting additional resources to Hawaii as the Indo- Asia-Pacific region continues to produce dynamic challenges to our national security interests.”

Hirono, a Hawaii Democrat and member of the Senate Armed Services Committee, said she “will work with the (Defense Department) to ensure they have all the information they need about Hawaii to make their decision.”

Defense experts say the Hawaii basing makes sense. But Japan, which is even closer to Southeast Asian hot spots where the new ship grouping is needed, is seen as the more likely candidate for a second forward-based amphibious ready group, with the possibility of the Pentagon doubling down on the one that’s already there.

Hawaii already has some of the Marines and aircraft — helicopters and tilt-rotor Ospreys — needed for the combat element of the force.

Having an amphibious ready group in Hawaii is something former U.S. Sen. Daniel Inouye suggested in 2006 after it became clear the aircraft carrier USS Carl Vinson would not be based in Hawaii as part of a homeport shift. The carrier went instead to San Diego.

Lt. Gen. John Wissler, head of U.S. Marine Corps Forces Command, said at a Center for Strategic and International Studies event in June 2016 that the Navy was committed to an additional amphibious ready group/Marine expeditionary unit presence in the Pacific as early as 2019.

The amphibious assault ship USS Bonhomme Richard, which has a flat deck like an aircraft carrier, along with the amphibious transport dock USS Green Bay and dock landing ship USS Ashland, make up the three-ship unit in Sasebo, Japan. The 31st Marine Expeditionary Unit, which deploys with it, has more than 2,200 Marines forward-deployed to Okinawa.

An amphibious ship like the USS America can carry 12 Ospreys, six F-35B short-takeoff and vertical landing jets, and 11 transport and attack helicopters, according to the Corps.

Where those Marines would be drawn from for a second Pacific amphibious group was still being examined, Wissler said.

“Whether those Marines come from the continental United States, whether they come from Hawaii, whether they come from the unit deployment program Marines in Japan, all those details are being worked out,” he said.

As part of the unit deployment program, Marines — including those in Hawaii — deploy to Japan for six or seven months.

Wissler said the goal is to create additional presence in southern Asia with existing forward-deployed naval forces focused on northern Asia.

The Center for Strategic and International Studies said in a 2016 paper that the U.S. amphibious force “is flexible, scalable and rapidly responsive,” adding, “As a result, the amphibious force is frequently called on during the initial phase of a crisis,” whether that’s for a natural disaster or conflict.

The Navy said the basing decision for another amphibious ready group is an ongoing process. Carl Schuster, a retired Navy captain and adjunct professor at Hawaii Pacific University, said Hawaii is a better choice than San Diego for the ship grouping, but operationally, Japan is the best choice if being forward deployed is the driver.

Hawaii has the port, maintenance facilities and Marine presence for an amphibious ready group/Marine expeditionary unit, but is farther away from Southeast Asia than Japan or Guam, Schuster said in an email.

Japan has the maintenance facilities, training areas and Marine units already present. Importantly, “in today’s budgetary situation, Japan tends to pay the U.S. facility costs and a portion of the ship maintenance costs — a great savings to the U.S. taxpayer and an unheralded and unappreciated Japanese contribution to mutual defense that our European allies do not make,” Schuster said.

The U.S. military presence on Okinawa remains a highly charged political issue, however, Schuster notes. Guam, meanwhile, lacks the maintenance facilities for the ships, he said.