“The United States is prepared to work toward reaching an understanding with Russia, along with our Transatlantic Allies and partners, on security issues of interest,” according to the document. “We are ready to consider arrangements or agreements with Russia on issues of bilateral concern, to include written, signed instruments, to address our respective security concerns.”In reality, the US missile defense system in Europe is part of the 'boil the frog' system that the US uses in many areas of it's foreign policy and unilateral strong-arming. The first instance of the project seems relatively inoffensive (the frog is in a pot of uncomfortably warm water), there is always some 'cover story' for what is being done, then little by little the heat is turned up (the frog gets used to the heat increasing a little from time to time). Eventually the heat is suddenly turned to boiling point, but by then the frog is exhausted by the heat and can't escape.
US 'leaked' anonymous document 2 February 2022
"Within the broader U.S.-Russian dispute over missile defense, a particular point of contention is the United States’ European Phased Adaptive Approach (EPAA). This initiative seeks to defend NATO against Iran.1 To this end, the United States has deployed SM-3 Block IB interceptors in Romania. It now plans to deploy more capable SM-3 Block IIA interceptors at the same site and at a second site in Poland. The launchers at each of these Aegis Ashore installations are adapted from the U.S. Navy’s MK-41 Vertical Launching System, which is used on ships equipped with the Aegis air and missile defense system to launch SLCMs and other missiles as well as SM-3 interceptors.When the Kremlin published the 2016 transcript of President Putin's remarks, it translated him as saying:
Russia believes that the EPAA may threaten its ability to target the United States with ICBMs. The United States’ November 2020 test of an SM-3 Block IIA interceptor against an ICBM-class target has added to Moscow’s unease.2 The U.S. Department of Defense contends that this interceptor “has the potential” to contribute to the defense of the homeland against “rogue states’” ICBMs, which have less capability to penetrate defenses than Russian ICBMs.3 Moreover, to be useful for homeland defense, SM-3 Block IIA interceptors would need to be deployed near the United States; systems located in Europe would be unable to catch a Russian ICBM. These considerations do not seem to have assured Moscow, however, which may have overestimated the capabilities of the SM-3 interceptor—in particular, its burnout speed (that is, its maximum speed, which is reached immediately after its motors have ceased firing).
Russia’s concerns about the EPAA extend beyond the interception of its ICBMs to the possibility that the launchers could be used to fire offensive missiles, particularly cruise missiles. In response, the U.S. Department of State has indicated that the “Aegis Ashore Missile Defense System” (a term that appears to include more than just the launchers themselves) “lacks the software, fire control hardware, support equipment, and other infrastructure” required for launching offensive missiles.4 It has also stated that “the defensive nature of the Aegis Ashore sites is documented in U.S. basing agreements” with Poland and Romania.5 Russia has made clear that it places little value on these assurances, noting, for example, that the United States has conducted a test launch of a cruise missile from a land-based MK-41 test launcher.6The United States and its NATO allies have compelling reasons to try to address Russia’s concerns. Most importantly, such concerns could spark inadvertent escalation. Moscow has threatened to attack Aegis Ashore installations preemptively in a crisis or conflict—presumably both to ensure the effectiveness of its nuclear deterrent and to prevent cruise missile attacks that could undermine its ability to wage a conventional war.7"
Carnegie Endowment for Peace 16 September 2021