Russia's problem, Todjaeger, is not the present day missile shield, but the long term implications of the missile shield both political and military. The missile shield is a club, an exclusive one. It's a club of developed countries against 2nd/3rd world powers with missiles. And when the shield was being negotiated, before the conflict in Ukraine, Russia had reasonable expectation to be included in this club. However it wasn't. Remember the success of US foreign policy vis-a-vis Germany and Japan? It was by including them in the security framework, and Russia was seeking a similar accommodation (minus the occupation, and military government). Russia is politically and economically not too different from many other Eastern European countries that not only are part of the EU and NATO but are unquestioningly regarded as democracies despite their corruption and oligarchical government. Being excluded from this showed Russian political leadership that they were still regarded as outsiders, and they likely drew the same conclusion that I have. They're outsiders because they're powerful. The Czechs, Hungarians, and Romanians, are allowed to have their corrupt local czars run things, because they're weak, and as long as they play along in foreign policy, the west can ignore their domestic problems. Russia can't get the same arrangement because Russia is powerful and wants to pursue an independent foreign policy. Therefore, no club membership.
On the military side it's not present day capabilities, but the future ones. If Russia is part of the missile shield then the shield can't even covertly be aimed at Russia. But if Russia is not part of it, then even if it's not aimed at Russia today, what's to stop it from being aimed at Russia 50 years from now? Let's say the Russia arsenal shrinks further, and at some point when Russia is temporarily weak again, and the west decides that it's within reach to upgrade the BMD to stop the now much smaller Russia arsenal. It's not inconceivable. It's not unrealistic. Hence the massive Russian nuclear buildup, the rush to replace older Soviet-era assets, and the constant chest thumping. Technology moves very quickly, and it's not inconceivable that, unless the Russian nuclear arsenal is vigorously advanced and upgraded, new technology makes it much easier to deal with. And if Russia is not part of the exclusive western club, then what guarantees Russian sovereignty, if not it's nuclear arsenal?
On the military side it's not present day capabilities, but the future ones. If Russia is part of the missile shield then the shield can't even covertly be aimed at Russia. But if Russia is not part of it, then even if it's not aimed at Russia today, what's to stop it from being aimed at Russia 50 years from now? Let's say the Russia arsenal shrinks further, and at some point when Russia is temporarily weak again, and the west decides that it's within reach to upgrade the BMD to stop the now much smaller Russia arsenal. It's not inconceivable. It's not unrealistic. Hence the massive Russian nuclear buildup, the rush to replace older Soviet-era assets, and the constant chest thumping. Technology moves very quickly, and it's not inconceivable that, unless the Russian nuclear arsenal is vigorously advanced and upgraded, new technology makes it much easier to deal with. And if Russia is not part of the exclusive western club, then what guarantees Russian sovereignty, if not it's nuclear arsenal?