The U.S. military most certainly has the capability to project force almost anywhere in the world on a moment's notice. They're always ready for war. The Army, Air Force, Navy and Marine Corps are on constant alert for the order to break through another nation's defenses and start aggressively installing a democracy.
Sure, the services usually work together to win wars. But what if a single branch were tasked to do the entire job on its own?
From destroying enemy air defenses to amphibious assaults, the Army could go it alone. Here's how.
The Air War
The air war is one of the areas where the Army would struggle most, but it wouldn't be a deal breaker. First, the Army has led an invasion force in support of the Air Force before. Apache helicopters fired some of the first shots of Desert Storm when they conducted a 200-mile, low altitude raid against Iraqi air defense sites.
The Army hit radar stations with Hellfire missiles, air defense guns with flechette rockets, and surviving personnel and equipment with 30mm grenades on the first night of the liberation of Kuwait. The raid opened a 20-mile gap in Iraq's air defenses for Air Force jets to fly through.
In an all-Army war, the first flight of Apaches could punch the hole in the air defenses and a second flight could fly through the gap to begin hitting targets in the country.
The biggest complication would be missions against enemy jets. Even if the Army purchased air-to-air weapons systems for the Apaches, they lack the range and speed of Air Force fighters. While they're capable of going toe-to-toe against enemy jets and winning, their relatively low mobility would make it challenging to be everywhere at once.
The Apache commanders would have to coordinate carefully with ground forces and other air assets to ensure they were providing anti-air at the right locations and times. To make up for the shortfall, Avenger, Patriot, and Stinger missile units would need to be stationed as far forward as possible so that their surface-to-air missiles would be able to fight off enemy fighters and attack aircraft going after friendly troops.
The U.S. Army does not specialize in amphibious operations, but it has conducted a few of the largest landings in history, including the D-Day landings.
The Army has three types of boats that can land supplies and forces ashore without needing help from the Navy. The Army crews on these boats are capable enough that the Navy considers them to be roughly equal to their own craft and doctrine calls for them to assist the Navy in joint amphibious assaults.
The star of an Army amphibious landing would be the Landing Craft Utility 2000, a boat capable of sailing 6,500 nautical miles and delivering 350 tons, the equivalent of five armed Abrams tanks and their crews.
The Army also rocks the Landing Craft, Mechanized 8 which can carry as much cargo as a C-17 and deliver it to an unimproved beach or damaged dock.
Finally, each of the Army's eight Logistic Support Vessels can carry up to 24 M1 tanks at a time, almost enough to deliver an entire armored cavalry troop in a single lift.
Army Logistics Support Vessels are heavy lifters that can drop a bridge to the coast, allowing trucks and armored vehicles to roll right off. (Photo: US Army Staff Sgt. Armando R. Limon)
Of course, soldiers would struggle against fierce beach defenders without the Marine Corps' Harriers or Cobras flying in support. The Army would have to rely on paratroopers dropped from Chinooks and attacks by Apaches and special operations Blackhawks to reduce enemy defenses during a beach landing.
The Army is a master of long-term logistics, but an Army that couldn't get help from the Merchant Marine, Navy, and Air Force would need to be extremely careful with how it dealt with its supply and transportation needs.
While helicopters and trucks could theoretically deliver everything the Army needs in a fight, they can't always do it quickly. A unit whose ammunition dump is hit by enemy fire needs more rounds immediately, not the next time a convoy is coming by.
To get supplies to soldiers quickly without Air Force C-130s and C-17s, the Army would need to earmark dozens of Chinooks and Blackhawks for surging personnel and supplies based on who needs it most.
This additional strain on those airframes would also increase their maintenance needs, taking them away from other missions. Logistics, if not properly planned and prioritized, would be one of the key potential failure points that commanders would have to watch.
So the Army, theoretically, could fight an entire enemy country on its own, using its own assets to conduct missions that the Air Force, Navy, and Marine Corps typically handle today. Still, the Army will probably keep leaning on the other branches for help. After all, the Air Force has the best chow halls.