This fall, the Air Force announced that A-10 Thunderbolt ground attack jets would join the fight against ISIS in Iraq. Earlier in the year, the Air Force sought to scrap the entire fleet of A-10’s, citing budgetary concerns and technical obsolescence as the major reasons. Congress refused to go along with the Air Force’s proposal, and recent events seem to have vindicated Congress.

In the fight against ISIS, the U.S. first deployed carrier-based F/A-18 Hornet fighter-bombers; evidently they didn’t get the job done.

The Air Force sent the A-10s, (affectionately called Warthogs), to perform a very specific mission: prevent Iraqi Government and Kurdish forces from losing by providing close air support. While experts have debated the long term feasibility of close air support in an era of anti-aircraft missiles, the impact of close air support cannot be debated; the effects are devastating.

Engineers designed the A-10 for close air support, and only close air support. The Warthog flies slow; the Warthog has heavy armor; the Warthog carries a lot of weapons, and the Warthog has enough fuel to stay in the air for a long time. In order to effectively support ground troops engaged in combat, a plane needs to fly low and slow, and it needs to stick around. A fighter pilot flying several miles above a battlefield at supersonic speeds simply can’t see the enemy most of the time; he will also burn through his fuel much faster than a Warthog pilot will. Only the A-10 can do what the A-10 does; the U.S Air Force has no other plane like it.

Still, many very smart people want to retire the thing, making it worthwhile to ask why. Writing in Forbes magazine, Loren Thompson had this to say, “Enemies lacked agile, man-portable air defenses. The subsequent appearance of those and other innovations has transformed warfare, making slow-moving, single-mission tactical aircraft like the A-10 antiques.”

Further, in an era of mandatory budget cuts due to sequestration, many have concluded that it would be less damaging to the Air Force’s overall capability to cut a single-mission aircraft, than to reduce the number of fighter bombers.

While it remains doubtful whether the A-10 could survive a war against an enemy with a modern and intact air defense network, it seems very unlikely that the U.S will face such an enemy in the near future. The biggest threat facing the United States comes from unconventional forces in faraway places. Enemies who do not have organized air defense networks, but enemies which cause a lot of trouble.

At the height of the Iraqi insurgency the Army purchased a vehicle it positively hated: The Mine Resistant, Ambush Protected Vehicle, or MRAP. The MRAP was heavy and tall, with minimal off road capability, but it saved a lot of American lives. The MRAP has no practical purpose outside of counterinsurgency, yet it was worth every penny.

Similarly, in a war against an opponent with advanced air defenses, the A-10 may be obsolete. However, if a platoon of infantry needs to escape a Taliban ambush the A-10 is far more useful than a supersonic stealth fighter that costs more than ten times as much.

Military hardware is just like any other tool; one doesn’t ask which tool is the best, but which tool is the right tool. If the past provides any guide to the future, the Warthog is precisely the sort of weapon for the type of war, and the type of enemy, America will face.