With tensions between Qatar and a Saudi-lead group of Arab countries (Saudi Arabia, Bahrain, the United Arab Emirates, and Egypt) increasing over allegations that Qatar funds terrorist groups, and a blockade being imposed, there is the question as to what would happen if this broke out into war.
Could Qatar hold on? Would Saudi Arabia have some new real estate?
Let's start with a look at the Qatari military. The blockade is one likely flashpoint, and the balance of naval forces is decidedly not in Qatar's favor. According to the "16th Edition of Combat Fleets of the World," the Qatari navy consists of seven patrol combatants equipped with MM.40 Exocet anti-ship missiles. This force is outclassed by the Saudi navy, the United Arab Emirates, and Bahrain, which combine for nine frigates, plus 10 corvettes and up to 30 guided-missile patrol combatants.
In essence, Qatar isn't about to break this blockade any time soon. Any naval battle will be very short – and will end with the Qatari navy on the bottom. The only question will be how much of an honor guard they will take with them.
It's important to note that eight of the Saudi-led coalition frigates are equipped with surface-to-air missiles, while the corvettes at least have point-defense systems like the Mk 15 Phalanx or launchers for the RIM-116 Rolling Airframe Missile.
So, what happens if the Saudi-lead coalition decides to roll into Qatar? Again, this will likely be a short fight. The Egyptian army and the combination of the Saudi army and Saudi National Guard would be operating under friendly skies very quickly.
According to FlightGlobal.com's World Air Forces 2017, Qatar has a single squadron of 13 Mirage 2000-5 fighters (nine Mirage 2000-5EDA, four Mirage 2000-5DDAs) on hand. Yes, they ordered 72 F-15QA Eagles, 18 Rafale Cs and six Rafale Bs, but those haven't been delivered.
As things stand right now, Bahrain's air force of 17 F-16Cs and 8 F-5Es could arguably take the Qatari air force on their own. That doesn't count what the United Arab Emirates or Saudi Arabia could throw in.
Qatar does have Patriot and THAAD batteries. These systems make for a formidable air-defense system. That said, the sheer numbers of planes from the Saudi-lead coalition ("World Air Forces 2017" notes that Saudi Arabia has 48 Eurofighters, 129 F-15C/S/SA, and 81 Tornado IDS while the UAE has 55 F-16E, 23 F-16F, and 49 Mirage 2000-5 fighters on hand) would likely overwhelm those defenses.
The ground battle would also be short. The Qatari army performed well during the Battle of Khafji in Desert Storm. But with one tank battalion, four mechanized infantry battalions, and an anti-tank battalion (according to GlobalSecurity.org), they are badly outnumbered by the eight brigades (two armored, five mechanized infantry, and one airborne) assigned to the Royal Saudi Land Forces. The Saudi Arabian National Guard brings 11 additional brigades.
Qatar has two trump cards to keep this crisis from going hot. One is the American presence at Al Udeid Air Base – in essence, the Saudi-lead coalition is not going to want to accidentally hit American personnel. The other is the fact that Turkey, under Recip Teyap Erdogan, is condemning the blockade, and Turkey has a formidable military of its own. But Turkey is a long way off, and may not be able to do much to stop a Saudi-lead invasion.