Why do the US and Russia not seem to support INF anymore?

Question

According to Time, Donald Trump plans to withdraw US from Intermediate-Range Nuclear Forces (INF) Treaty:

President Donald Trump revealed Saturday the United States intends to withdraw from a 31-year-old nuclear weapons agreement with Russia, delivering a severe blow to the arms control regime that helped preserve peace since the Cold War.

“Russia has violated the agreement,” Trump said. “They’ve been violating it for many years. And I don’t know why President Obama didn’t negotiate or pull out. And we’re not going to let them violate a nuclear agreement and go out and do weapons, and we’re not allowed to.”

On the other hand, Russia accused the US of violating the treaty:

The Russian Foreign Ministry declared that the U.S. plans to deploy the Aegis missile defense system in Poland and Romania is a violation of the INF Treaty. The Romanian location was stood up in 2016 and is operational.

According to Times, this treaty had great importance, so I am wondering why it does not seem to be supported by any of the two countries:

(..) was the first and only nuclear arms control agreement that ever eliminated an entire class of nuclear weapons.

Question: Why do US and Russia do not seem to support INF anymore?

Answer 1

US tries to undermine Russian nuclear deterrence

INF Treaty was a product of Cold War, and relative Soviet weakness at that time. To understand this, first you must understand that intermediate and short range missiles presented (and still present) a larger threat to the Soviet Union (Russia) than to the US. The reason is simple, Soviet and Russian intermediate missiles could not reach US (except Alaska), but US & NATO missiles could hit European part of USSR and more. Since IRBMs are cheaper and smaller then ICBMs, plus flight time is shorter, they could theoretically have been used as a first strike weapon against the USSR. Later, the US added ground based BMG-109G which further complicated situation. Soviets on their part had very potent RSD-10 Pioneer, arguably better then NATO counterpart and in larger numbers. Soviets did not plan to use them against US mainland, but could hit targets in Western Europe.

As mentioned before, since IRBMs have a short flight time, it was very unlikely either of the sides would have enough time to detect them and launch retaliatory strike on opponent. Therefore, it would be prudent to launch first. This is especially true for the USSR. The situation could escalate, so both sides finally agreed to remove them completely. By that time, the Soviet Union was already in crisis, so the treaty was somewhat unfair to them - only ground base missiles were removed but air and naval remained. The Soviet Union was at a disadvantage because the danger of air and naval nuclear missiles remained, and they had spent considerable resources to develop ground based IRBMs (Soviets and Russians always considered ground forces as a key element, unlike US).

Unfortunately, end of Cold War didn't end US and NATO expansion plans. NATO got to Russian borders, incorporating many of former Warsaw Pact states. Since Russia didn't want and could not spend so lavishly on conventional forces, it relied primarily on its nuclear forces for deterrence against potential NATO intervention (like in Iraq, Yugoslavia, Afghanistan, Libya, Syria etc ...). To undermine that, NATO started building anti-ballistic missile defense, and withdrew from another treaty - Anti-Ballistic Missile Treaty in 2002.

Final chapter of the saga is Russian response. Since Russia could not afford another arms race, they started developing an asymmetrical response. The NATO missile defense system relies on sites in Poland, Czech Republic and Romania, Russia started developing Iskander missile to target them. Officially, Iskander's range is below 500km, so it is not covered by INF treaty. Iskander is certainly not as capable as RSD-10 Pioneer, but it could disturb NATO missile defense in case of war, and also has upgrade potential to go beyond 500 km.

Since Iskander endangers US & NATO strategic goal of reducing Russian nuclear capabilities, they use it as an excuse to withdraw themselves from INF treaty. If they do that, world would become more dangerous place, as Russia would be forced to expand its nuclear forces with new weapons, and more importantly with various Dead Hand systems to launch those weapons automatically (without man in the loop) in case of NATO decapitating strike. Of course, any failure in such system could be potentially devastating for whole mankind.

Answer 2

There is, of course, no single answer, but a number of things have changed since the Intermediate-Range Nuclear Forces (INF) treaties were created about 30 years ago, that might be helpful in understanding why leaders on both sides have made statements questioning value of the bilateral agreement to their respective countries.

But concerns not directly related to INF must also be considered as well. In the view of NATO, the Annexation of Crimea by the Russian Federation in 2014, and Putin boasts of new Russian nuclear weapons in 2018 have set the stage for deterioration in international relations. But specific issues related to the INF treaties are probably most relevant:

Sunsetting of On-site Inspection

When the INF treaties were signed, they included a set of verification measures that permitted the parties to gain confidence that the other terms of the treaty were being followed. One of these verification measures, on-site inspections, came to an end in 2001. With the inspection part of the agreement no longer in effect, it has become difficult for either side to verify compliance of the other.

Proliferation of Technologies

The INF agreement was bi-lateral, it only restricted two countries. Since then, other countries have developed both nuclear weapons, and missiles with a ranges sufficient to be threatening to both sides of the original agreement. Today China, France, India, Israel, North Korea, Pakistan and the UK are thought to have such capabilities.

Only Ground Launched Missiles Covered

The INF agreements were limited to ground launched missiles, and did not cover either air- or sea- launched weapons of similar range. These systems further complicate the matter of verification of limits to ground launched missiles, and both side's arguments that the other is not in compliance involve systems originally designed for shipboard use.

Confusion between Offensive and Defensive Missiles

In the question reference is made a missile defense system in Poland and Romania. The NATO position on this is that these are strictly defensive missiles, including anti-ballistic missiles (ABMs), that are not covered under the INF treaty. The missiles in these locations are US built SM-3 interceptors, but the claims from Vladimir Putin seem to be that the ground facilities could be used to fire some hypothetical ground launched cruise missile.

Article VII of the INF is explicit that interceptors like the SM-3 are not covered:

3. If a GLBM is of a type developed and tested solely to intercept and counter objects not located on the surface of the earth, it shall not be considered to be a missile to which the limitations of this Treaty apply.

Putin's accusation may have been the breaking point for the INF treaty. Defensive missiles had previously been limited under the 1972 ABM treaty, which the US withdrew from in 2002. Russia has produced and deployed numerous ABM systems, including the A-35, A-135, and A-235, and indications are that the S-500 ABM is targeting deployment in 2020. Attempts to limit NATO deployments of ABMs under INF interpretation seem inappropriate, but could drive the INF treaty to end.

Timeline of events regarding withdrawal from INF

In October 2007, Luke Harding reported that Vladimir Putin had threatened to withdraw from a treaty generally assumed to be INF. The article quotes Putin as saying:

We need other international participants to assume the same obligations which have been assumed by the Russian Federation and the US.

It goes on to report Putin said:

If we are unable to attain such a goal... it will be difficult for us to keep within the framework of the treaty in a situation where other countries do develop such weapons systems, and among those are countries in our near vicinity,'

Beginning in 2013 the US raised concerns over an apparent violation of the INF agreement, specifically in In a July 2014 unclassified report, the U.S. State department said:

The United States has determined that the Russian Federation is in violation of its obligations under the INF Treaty not to possess, produce, or flight-test a ground-launched cruise missile (GLCM) with a range capability of 500 km to 5,500 km, or to possess or produce launchers of such missiles.

…

In 2013, the United States raised these concerns with the Russian Federation on repeated occasions in an effort to resolve U.S. concerns. The United States will continue to pursue resolution of U.S. concerns with Russia

In an June 2015 unclassified report, the U.S. State department reported counter-claims by Russia:

In bilateral meetings with U.S. officials relating to the INF Treaty, Russia claimed that the Aegis Ashore Missile Defense System launcher was capable of launching INF-range offensive ground-launched ballistic or cruise missiles and therefore, was inconsistent with the Treaty. As explained in detail to Russia, the U.S. Aegis Ashore Missile Defense System is fully consistent with U.S. obligations under the INF Treaty: it was designed and tested for missile defense purposes only and does not have an offensive capability. As such, the Aegis Ashore Missile Defense System is not a prohibited launcher. Russia also again raised concerns relating to armed unmanned aerial vehicles (UAVs) and ballistic target missiles, both of which we previously had addressed in the Special Verification Commission.

In February 2017, the New York Times reported Russian had secretly deployed missile in question and indicating it carried the NATO designation SSC-8 (Russian designation 9M729). It went on to say:

The Obama administration had sought to persuade the Russians to correct the violation while the missile was still in the test phase. Instead the Russians have moved ahead with the system, deploying a fully operational unit.