After Turkey insisted on acquiring the Russian-made S-400 air defense system, the Trump administration wisely decided July 17 to remove Turkey from the F-35 fighter program. Yet, in addition to Turkey, three U.S. partners — Saudi Arabia, Qatar and India — are either considering or procuring the S-400. They would be wise to reconsider.

Tass, the Russian news agency, reported in February that Russia and Saudi Arabia were “holding additional consultations on a contract” to supply Riyadh with the S-400. Saudi Arabia and the United States have enjoyed a long-standing security relationship, as both countries seek to counter Iran. However, Riyadh’s tactics in Yemen and deplorable human rights record, as well as the brutal murder of Jamal Khashoggi, have severely strained the U.S.-Saudi relationship.

If Riyadh adds insult to injury and procures the S-400, it could represent a tipping point in the relationship with Washington — especially on Capitol Hill.

Qatar has also shown interest in the S-400 and apparently engaged in “advanced” talks with Russia earlier this year. Qatar hosts the Al Udeid Air Base, the largest U.S. military installation in the Middle East and home of U.S. Air Forces Central Command, as well as over 11,000 U.S. and coalition service members. According to the Pentagon, the base “has served as the primary staging ground for most air operations in the campaign to defeat ISIS.”

Should Qatar acquire the S-400, the Pentagon may decide it cannot operate U.S. F-35s from Al Udeid. As the White House correctly noted, “the F-35 cannot coexist with a Russian intelligence collection platform that will be used to learn about its advanced capabilities.” The F-35 will be the backbone of U.S. air power for decades to come. The U.S. cannot risk Russian compromise of its most important fighter.

An inability to fully utilize Al Udeid would hurt American military effectiveness in the Middle East and undermine the value of the air base to the Pentagon. If Qatar is seeking to gain the upper hand in its standoff with Saudi Arabia and accrue admirers in Washington, acquiring the S-400 seems an odd way to do it. Qatar may think that Al Udeid Air Base provides leverage, but Washington has other options, and acquiring the S-400 would reduce the value of the base to the United States in the coming years.

India, meanwhile, is an increasingly important partner for the U.S. in Asia. The world’s oldest democracy and the world’s most populous share many interests. The bilateral relationship between the U.S. and India has the potential to become a leading contributor to regional and international security, stability and prosperity in the 21st century. That is why both capitals would be wise to look for further opportunities to broaden and deepen cooperation on a variety of mutual challenges — including China and terrorism.

Yet, in 2018, India agreed to pay more than $5 billion for five S-400 squadrons, which are set to be delivered in 2023. That would be a huge mistake. If New Delhi procures the S-400, it would represent a significant and persistent thorn in the bilateral relationship — damaging the mutually beneficial progress achieved in recent years.

Each of these three countries certainly has a sovereign right to purchase weapons from whomever they wish. However, before they exercise that right, Riyadh, Doha and New Delhi should carefully examine the case of Turkey and consider the costs and benefits of acquiring the S-400. The response to Ankara on Capitol Hill and the Trump administration’s eviction of Turkey from the F-35 program should eliminate hopes in any foreign capital of quietly acquiring the S-400 without eliciting a strong bipartisan American reaction.

Leaders of both parties in Washington will construe decisions related to the S-400 as an indicator of what kind of diplomatic, economic and security relationship a government hopes to have with the United States for years to come. Before buying the S-400 from Moscow, key U.S. partners should think twice.

Bradley Bowman is senior director for the Center on Military and Political Power with the Foundation for Defense of Democracies, where Andrew Gabel is a research analyst.

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