The U.S. Navy's Aegis Combat System is primarily a defensive weapon (Aegis was first used in English as a synonym to "shield"), but it can also be used to attack enemy land and sea targets. Many American allies have sought to have Aegis installed on their ships or land installations, a trend that Russia hates and often protests.
The Aegis Ashore Missile Defense Test Complex fires during a flight test in December 2018.
(Missile Defense Agency Mark Wright)
Aegis is a bit of a legend in the military community, especially air defense. The core of the system is an extremely capable radar that can operate through a months or even years-long cruise at sea if properly maintained. This, of course, allows the operators to track threats from ballistic missiles to navy vessels to surfaced submarines. But, when properly wedded to missiles, the Aegis gets the ability to attack these targets on land, at sea, or in the air.
For America's allies around the world, this can be a godsend. Japan has to constantly worry about the possibility of a Korean nuclear missile attack. So, a package deal for highly capable radar and compatible missiles is highly desirable. But when Japan bought two of them for use ashore, Russia lodged protests.
Russia is a regional power. While it doesn't have the might or clout of the Soviet Union, it did inherit a lot of the Soviet treaties and nearly all of the Soviet nuclear weapons when that nation collapsed. And so it doesn't want to see its own missiles made obsolete in the unlikely chance of war with Japan, especially when it can lodge protests under treaties like the Intermediate-Range Nuclear Forces Treaty.
But when it comes to Europe, Russia is even more sensitive. The Soviet Union used to hold sway over all of Eastern Europe, but American diplomatic expansion after the Soviet collapse has allowed the U.S. to find friends in places like Ukraine, Poland, Estonia, and more that border Russia or its enclave at Kaliningrad.
And for the past few years, an American and European agreement has seen Aegis systems deployed on land in places like Romania and Poland with more sites to come. But Aegis Ashore has one huge difference from the Aegis systems at sea: what missiles its launchers can house and fire.
While Aegis ships at sea can be equipped with everything from Tomahawk Land-Attack Missiles to the entire family of Navy Standard Missiles, Aegis Ashore was initially equipped with just the ballistic defense missile known as Standard Missile-3. But some American leaders have floated the idea of adding the missiles SM-2 and SM-6, missiles capable of killing enemy cruise missiles, jets, and helicopters.
Aegis Ashore Site in Poland under construction in August 2019.
(U.S. Navy Lt. Amy Forsythe)
For Russia, this creates obvious problems. While it has sought to fight in the so-called "grey zone" just short of open warfare in the last few years, it has previously invaded neighbors like Georgia and would like the option of doing so again. A network of missiles that could shred its jets would make the situation worse.
But Russia's diplomatic protests against Aegis are all aimed at the Tomahawk missile, a potential treaty-violating weapon that would truly terrify Russia if deployed near its borders in large numbers. Aegis at sea can control these missiles and rain them down on America's enemies like it did against Syria.
When America fired Tomahawks in the recent Syria strikes, Russia declined to engage the missiles or American bombers with its own air defenses, possibly because it isn't certain it can actually take down the Tomahawks in significant numbers. Though, again, Aegis Ashore is specifically configured to be incapable of firing Tomahawks.
Russia is so against Aegis Ashore installations that it deployed strategic bombers to Crimea earlier this year to threaten the installations and NATO.
But as long as Aegis systems are going in across the world, Russia is going to be protesting. The Tomahawk problem is just the part they can protest against. It's likely that the real problem for Russia is its missile threat being negated and its bombers and fighters threatened.
But, you know, sucks to be you, Russia. Get on our level.