Russia's Reactions to the US-NATO Missile Defense Shield

Over the past two decades, the Russian military has upgraded certain categories of its military equipment (e.g., nuclear warheads). As part of this military modernization strategy, some of the old types of missiles are replaced with the new ones  including new submarine-launched and ground-launched intercontinental ballistic missiles (ICBMs). Additionally, the Russian military has begun new weapon research and development that had previously little place in the country's defense structure. The new program which started in the mid-2000s, include the production of cruise missiles, hypersonic missiles, and unmanned submarines. The evidence now shows that this program will be continued in the coming years.
The main research question is as follows: Why has Russia decided to modernize its nuclear warheads in recent years? In the hypothesis, it is asserted that among all factors which have prompted Russia to upgrade its nuclear warheads, the United States and NATO policy of deploying missile defense shields has had the greatest impact on Russia’s military modernization program. Since Russian leaders consider the establishment of missile defense systems by the NATO allies as an existential threat to their country, it comes as no surprise that they have been investing in a program with the aim of acquiring new nuclear capability for deterrence as well as for defense. The new weapon systems are developed to enhance Russia’s ability to retaliate in response to any aggressive actions including a nuclear attack by the US and NATO.
In order to find suitable answers to the research question, the authors, with a descriptive-explanatory approach, rely on qualitative conceptual content analysis of government documents (such as national security strategy document) and the  statements made by the high-ranking Russian officials. Furthermore, the views of international relations scholars, security specialists, and experts on Russian military affairs are explored for the purpose of descriptive data collection and analysis.
Two factors have contributed more than any other variables to the strategic culture of the Russian politicians and people: 1. The peoples’ experiences of the recent decades; 2. The leaders’ belief system which is influenced and shaped by geostrategic factors, military technology, and military organizations. Hostile and rival pawers’ d
eployment of the defense shields throughout Europe deprives Russia of the advantage of nuclear retaliation, thus giving the West the advantage of a first strike. This situation might shift the geopolitical balance to the disadvantage of Russia. Given the past history of Russia as a great power, it is basically inconceivable for the Russiansto accept the role of a minor power or a subordinate partner in the international system. Despite all itsshortcomings (e.g., a relatively low economic and technological development in the Global North), USSR(and later Russia as its leadingsuccessor state) has been regarded as amilitarily dominantstate in the post-WWII  international system.
From the point of view of the Russian leaders, the West's claims about the need for the missile defense shield to counter Iran's missile threats are exaggerated. Russia has hundreds of nuclear warheads that enable its leaders to deal a fatal blow to any enemy in any part of the world. The missile defense shield deprives Russia of this advantage. Even if the US and NATO missile defense shield poses no direct threat to the Russians, Moscow considers its deployment in Europe psychologically a negative, detrimental, and debilitating political move by Russia’s adversaries.
In response to the missile defense shield, Russian leaders initially sought security guarantees from the West, but Western leaders refused to accommodate Moscow’s request. They did not even accept Russia's offer to cooperate in NATO's missile defense shield plan in Europe, or even to grant Moscow access to the Qibla radar station in Azerbaijan. In response, Russia first suspended its membership in the Conventional Armed Forces in Europe (CFE) Treaty, and subsequently developed new delivery systems including the following ICBMS: a) the Sarmat  ICBM with a speed of 25,000 km per hour, a range of 10,000 km, and carrying 10 to 25 warheads; b) Yars ICBM, with a range of 11,000 km which can carry 6 to 30 nuclear warheads; c) Avangard rockets, reportedly with a record speed of 20 times the speed of sound, which means that no missile defense shield can destroy it; d) Burustenik cruise missile, which can be hidden from missile defense shield radars due to its low altitude flight; e) Alexander nuclear missile, with a speed of up to 2600 meters per second, which can  neutralize missile defense shield; f) advanced Borya-2 submarines capable of carrying sea-based Bulava ballistic missiles, which have a range of 8,000 km; g) Poseidon nuclear unmanned submarine, which was designed to destroy coastal areas. With these initiatives, Russian leaders modernized their nuclear warheads and were able to maintain their nuclear balance with the West and maintain their position as one of the world's two leading nuclear powers. Russia's military innovation includes the production of missiles that the missile defense shields of the US and its western allies cannot intercept and destroy. The deployment of these offensive systems has increased Russia's ability to deter and defend against the West.