The biggest threat Russia poses from Kaliningrad is its deployment of Iskander-M ballistic missiles.
Since the accession of the Baltic nations into NATO, the region of Kaliningrad has been considered a strategic hotspot. Sandwiched between Lithuania and Poland, it is one of the major Russian ports that has access to Baltic Sea. Due to its location, Russian missiles and ships stationed in the region have the capability to deny significant areas of operation to American or European forces. Russian units stationed in Kaliningrad have a very strong preemptive strike capability against the Polish and Baltic militaries, as well as any of their North Atlantic Treaty Organization (NATO) partners in the region. Of all of these threats, the biggest one Russia poses from Kaliningrad is their deployment of Iskander-M ballistic missiles. NATO, including the nearby Baltic nations and Poland, currently have very little ability to counter these Russian forces.
With a published range of over 400km and a speculated range of over 500km, the Iskander would be capable of attacking every single Polish naval installation on the coast, as well as any installations in the Baltic states. While Poland’s procurement of the defensive ABM-capable PAC-3 Patriot missiles may mitigate this problem, it’s not clear whether countering the Iskanders is a planned role for the Patriots. Poland certainly would be wise to do so, as the Patriot is the only system in the region that has a chance of intercepting an Iskander. Older systems such as the Newa variants used by Poland are only effective against slow cruise missiles and aircraft. At the same time, Russia is phasing out its own older Tochka-U missiles based in Kaliningrad in favor of more Iskanders.
Recommended: How China Plans to Win a War Against the U.S. Navy