As Russia begins delivering the S-400 missile defence system to India, an American think tank has warned that US sanctions against New Delhi could lead to blowback between the two allies.

The Biden administration said last week that it has not yet made a decision whether to issue a waiver to India for violating the Countering America’s Adversaries Through Sanctions Act (CAATSA) regarding the purchase of the Russian missile system.

The sanction discussions come as a senior Russian official said that the deliveries of S-400 surface-to-air missile systems are moving forward as planned. New Delhi signed the $5 billion-dollar deal with Russia in 2018 to buy five of the S-400 missile systems despite warnings of sanctions by the Trump administration at the time.

“CAATSA sanctions will trigger significant Indian political blowback, setting relations back a decade,” a November report by Stimson Centre titled Toward a Mature Defence Partnership said.

“The United States should either issue India an enduring waiver or apply very light, symbolic sanctions once, with sufficient forewarning and dialogue with Indian leadership to mitigate political repercussions,” it added.

CAATSA And India

CAATSA, signed by Donald Trump in 2017, authorizes the US to impose sanctions on countries purchasing defence hardware from Russia. The law, which has been used to impose new sanctions on Iran, Russia, and North Korea, aims to discourage global Russian arms purchases.

However, two influential US senators, Mark Warner (D-VA) and John Cornyn (R-TX), have urged President Joe Biden not to impose CAATSA provisions against India.

“We strongly encourage you to grant a CAATSA waiver to India for its planned purchase of the S-400 Triumf surface-to-air missile system,” the two Senators wrote in a letter last month. “In cases where granting a waiver would advance the national security interests of the US, this waiver authority, as written into the law by Congress, allows the President additional discretion in applying sanctions.”

India has been bolstering its military capabilities with eyes on neighbours including China and Pakistan. It purchased the Russian missile system, known for tracking numerous incoming objects including fighter jets and launching multiple appropriate missiles in response. The missile system can pick up objects up to a distance of 1,000 kilometers (620 miles).