Japan’s planned purchase of almost 150 US-built F-35s stealth fighters – at an estimated price tag of somewhere between $8 billion and $11 billion – is a massive and complex undertaking for multiple reasons.

It makes good sense in terms of Japan’s alliance with the US and may also provide a political-economic hedge against potential trade pressure from Washington. Tactically, the seaborne variants, to be deployed on the platform of two Izumo-class helicopter carriers which will be converted to the aircraft carrier role, will extend Japan’s airborne strike capabilities. And the overall buy replaces a fleet of aging aircraft.

However, the purchase is problematic from a budgetary standpoint, and could also hinder native arms developments. The creation of a new fleet air arm demands a wide range of back-up and logistic requirements to be put in place, while the new carrier requirements could detract from other necessary naval capabilities.

Moreover, the massive buy of US weapons could hinder potential European partnerships.

Budget battle ahead

Japan’s decision to buy so many of the pricey F-35s comes at a time when Prime Minister Shinzo Abe and his Liberal Democratic Party are also looking at a massive outlay for a pair of the US Aegis Ashore anti-missile systems.

The two procurements will put an enormous strain on Abe as he tries to figure out how to keep the entire Japanese defense apparatus in balance with only modest budgetary increases.

The more spent on these programs means fewer funds available for native developments, such as Japan’s next-generation unmanned aircraft and submarines, as well as new and perhaps revolutionary anti-submarine warfare platforms which could prove to be significant game changers in the region.

Experts see a huge budgetary challenge shaping up.

“Under the new mid-term defense program, spending would grow at a 1.1% per year average, outpacing the 0.8% annual grown in the current spending program. Defense spending will still not exceed the 1% of GDP cap that Japan has long adhered to (unless Japan switches to the NATO method of calculating defense spending). It is now about 0.9% of GDP,” said Professor William Brooks of the Johns Hopkins University’s School for Advanced International Studies in Washington.

“Moreover, 80% of the defense budget goes for payments for previously purchased equipment and personnel expenses. So there is not a lot of leeway. The rest of the budget will be eaten up by the expensive F-35s.”

“The budget is very tight, (and) the bottlenecks are multiple. Recruitment and retention the greatest of all. The Maritime Self Defense Force has too many ships already and too few sailors now. How that will work with an expanded force, nobody knows,” Garren Mulloy, Associate Professor of International Relations at Daito Bunka University in Saitama, Japan told Asia Times.

“Aegis Ashore and (the F-35 acquisition) are two massive money-eating projects.”

The right plane for the job?

The F-35 is a single engine aircraft, but Japan’s Air Self Defense Force has always wanted its next warplane to be a twin-engine fighter, said Mulloy. “While the F-35 is stealthy, it has a shorter range and less air combat capability than the F-15 and possibly the F-2 as well,” said Mulloy, referring to the home-grown variant of the American F-16.

The carrier-based variant of the F35 will, of course, add force-projection range to Tokyo’s asset portfolio as it will be based on an ocean-roving platform. But the introduction of a fleet fighter wing creates multiple issues.

Mulloy describes the F-35B as providing “a very limited capability at very high cost … The F-35 is also very expensive to service and demands all-new simulator systems, etc. The F-35B is far from the ideal aircraft for Japan.”

It is not just the F35B itself. The conversion costs for the two helicopter carriers, demands for escort vessels and logistical support, as well as a massive aviation support and training network, also need to be taken into account, Mulloy said.

But other experts insist that the F-35 purchase makes sound sense, given the fleet of aging aircraft that need to be replaced.

“The reason Japan is purchasing 147 F-35s is to replace the last of three squadrons of F-4EJ/RF-4 Phantom IIs that will retire in 2020 and after that, about 100 F-15J/DJ Eagles that were built to an earlier standard and are more difficult to upgrade,” said Mike Yeo, Asia Reporter at Defense News.

“Japan has already set the 2030s as the planned entry into service date of its next-generation fighter. This will replace Japan’s fleet of indigenous Mitsubishi F-2 fighters, and possibly after that, the newer F-15s that Japan plans to upgrade,” Yeo said.

He added that the F-35 buy now planned makes sense from a long-term scheduling standpoint, as well from both an economy of scale and an alliance standpoint.

The non-tactical benefit

Certainly, with Abe wary of the Donald Trump administration’s unpredictability, the political benefits for the Japan-US alliance associated with the deal are appealing: The massive purchase of the top-end fighters should help to keep Tokyo out of Washington’s trade-war crosshairs.

“Japan has been criticized by the Trump administration for the over $60 billion trade deficit and this F-35  purchase addresses Washington’s demands that Japan purchase more US defense equipment to offset the trade imbalance,” said Professor of National Security Affairs Terry Roehrig at the US Naval War College, who is also the Director of the Asia-Pacific Studies Group.

The Japanese acquisition might also fill an upcoming hole in US export sales. “There is also a likelihood that Turkey will be excluded from purchasing the F-35 over its acquisition of the Russian S-400 anti-aircraft system,” Roehrig said. “Japan’s increased buy of the plane will help offset this loss.”

Both the US Air Force and US Marines will be deploying a large number of F35s warplanes on Japanese soil in the near future; Japan’s purchase should make for excellent cooperation and interoperability.

But while Japan will be well-served by acquiring a certain number of F-35s, Japan needs to be more open to developing closer ties with European partners.

“There is great defense synergy between European partners and Japan which could work with fighters as well,” said Mulloy. “Put all your eggs in the F-35 basket and the chances of failure, or of US sanctions, which have suddenly become believable in the Trump era, become real concerns.”

Beyond the aerial space

Roehrig is keeping a sharp eye on China’s expanding and increasingly more capable submarine force. This ominous Chinese trend worries Roehrig, who is concerned that in the process of re-tasking its Izumo-class ships to support F-35Bs, Japan may risk adversely impacting Tokyo’s anti-submarine warfare (ASW) capabilities.

“Placing these planes on Izumo-class ships will provide Japan greater reach and allow it to more effectively protect its southern islands from Chinese intrusion,” said Roehrig. “Yes, Japan will gain increased reach and combat power – but will it come at the expense of these vessels’ excellent ASW capabilities? Now, these ships carry 12 to14 helicopters that are very effective at detecting submarines. Removing helicopters to make room for aircraft would decrease its ASW capability.”

All this suggests that Japan has much to consider as it plans to greatly expand the role of the F-35 JSF and F-35B. The big questions are how many F-35s are needed and how will this number impact other vital Japanese defense priorities.