Senior brass in the Air Force have been trying to retire the A-10 Thunderbolt II, commonly called the “Warthog” for its less-than-comely appearance, for years. Faced with tough budget constraints, the Air Force has tried to prioritize its core missions, including a long-term search for a new strategic bomber dubbed the “Long Range Strike Bomber Program.”

The other priority for the Air Force has been the most expensive weapons system in history, the F-35 Joint Strike Fighter. The futuristic, stealthy jet comes in Air Force, Navy, and Marine Corps variants. Theoriginaldesign was elegant and efficient: One platform, with minor differences between variants, could replace the Navy’s F-18 carrier-based fighters, the Marine Corps’ Harrier “jump jets,” and a number of Air Force aircraft, including the A-10.

The minor differences grew over the course of the program, until the three variants were more dissimilar than similar, sharing only about a quarter of their parts. As the designs diverged, the costs mounted, topping $1.5 trillion. Critics, of whom there are many, called the program “too big to fail”—no one wanted to consider ending the program after so much taxpayer money had been dumped into it, and no one wanted to take responsibility for the program going sideways.

The A-10, on the other hand, was small and old enough to retire. As the wars in Iraq and Afghanistan died down during the Obama administration, the Air Force saw an opportunity to move away from close-air support, the singular job of the A-10.

The Warthog was designed after the Vietnam war, when the Air Force realized that it lacked an airframe that could provide battlefield protection for ground forces, especially against entrenched or armored enemies. The airplane Fairchild Republic built to meet that need is, essentially, a flying machine-gun nest. The key features of the plane’s design are its giant, center-mounted cannon built to shred Soviet armor with 3,900 30mm depleted-uranium rounds a minute. Just behind the cannon, ensconced in a protective armor tub, sits the pilot. Behind him, straight wings capable of carrying myriad bombs and missiles, two jet engines—and not much else.

The A-10 has seen action in Kuwait, Iraq (twice), the Balkans, Afghanistan, Libya, and most recently against ISIS. When the planes were redeployed back to the Middle East in October of 2015, the clamor for their retirement subsided somewhat.

Most of the plane’s protectors, however, have been on Capitol Hill. Congress has consistently authorized and appropriated money for programs to extend the Warthog’s service life, including Monday's authorization for a wing replacement program. GOP Rep. Martha McSally, who once flew A-10s, has been a critical proponent of the Warthogs. When the Air Force suggested retiring three of the nine active squadrons, she balked, insisting, “From my view and my experience, if we need that capability until a proven, tested replacement comes along, nine squadrons is the absolute minimum.”

The Pentagon quietly succumbed to congressional pressure in its 2017 budget request, “indefinitely freezing” the aircraft’s retirement.