While India is all set to finalise and sign the deal with Russia for buying the lethal S-400 Triumf air defence missiles (NATO code: SA-21 Growler), the United States can use the Countering America's Adversaries Through Sanctions Act (CAATSA) to stop the defence agreement.
However, Defence Minister Nirmala Sitharaman has made it clear that the US cannot stop the deal as CAATSA cannot be imposed by the United Nations and so India is insulated from it.
But international defence experts have told Russian news website Sputnik that the US has several reasons to stop India from acquiring the Russia air defence missiles which are way ahead of similar western systems and can prove to be a game changer in the event of a war in the subcontinent.
According to journalist, foreign affairs analyst and military observer Rakesh Krishnan Simha the Russian S-400 Triumf are currently the most powerful anti-aircraft and anti-missile system in service. He pointed out that the S-400 has been modelled on the famous S-75 missile that brought down the American U-2 spy plane over Russia in 1960 at the height of the cold war.
India, China, Turkey and Saudi Arabia are keen to have the S-400 in their arsenal because the missile system is extremely accurate and highly lethal. "With a tracking range of 600 km; the ability to destroy hostile aerial targets at a range of up to 400 km and altitude of 30 km at a blistering speed of 17,000 km an hour, the S-400 is a truly lethal air defense weapon," he said.
US Arms Service Committee Chairman Mac Thornberry had in May 2018 claimed that the US administration, as well as the Congress, was concerned about the S-400 missiles. "There is concern that any country and not just India that acquires that system will complicate our ability to work towards interoperability together," he said.
Simha explained that S-400 is almost a strategic non-nuclear missile and in such deals, the buyer and seller have greater interest. Moreover, Russian made weapons have proven to have longevity and the S-400 could serve the Indian armed forces for the next few decades.
The US also is eyeing the lucrative Indian defence market and any major deal with Russia will be a roadblock. Since India is one of the biggest weapons importers, so other countries too look forward to it before finalising any major deal.
Once India acquires and deploys the S-400, the entire power equation with Pakistan, which has been a US ally for decades, will change. Simha claimed that the S-400 will turn a defensive system into an offensive system. India will be able to track and neutralise any Pakistani aerial threat - be it a fighter-bomber or a missile - by deploying "just three S-400 battalions", a situation which the US will under no circumstances accept without protest.
Several US lawmakers have raised their voice against Turkey, a NATO member, getting the S-400 missiles from Russia. Turkey is also in the process of acquiring the US-made F-35 stealth fighters and US official fear the S-400 may expose the jet's secret capabilities and vulnerabilities as the missile is capable of shooting down "stealth" aircraft.