A soldier looks at a radar screen of an S-400 missile system at the Vostok 2018 military exercise, which involves troops from China and Mongolia. Photo: TASS via Getty Images

Military hardware is Russia's second-biggest source of income after oil, and the S-400 surface-to-air missile is one of the country's most advanced and marketable weapons systems in recent years.

Why it matters: Because of its capabilities, several countries including China, Saudi Arabia, Turkey, India and Qatar have said they are willing to buy the S-400. Almost every government that announced it was planning to buy the system was threatened with some kind of diplomatic retaliation from the U.S., NATO or adversaries. The reason for this blowback, according to several experts Al Jazeera interviewed, is not only because the S-400 is technologically advanced, it also poses a potential risk for long-standing alliances.

  • "The S-400 is among the most advanced air defense systems available, on par with the best the West has to offer," said Siemon Wezeman, senior researcher with Stockholm International Peace Research Institute's (SIPRI) arms transfers and military expenditure program.
  • "It's intended to be a one-size-fits-all missile system. It can be configured with long-range, semi long-range, medium-range and even short-range weapons systems, depending on how the individual user wishes to configure the S-400," said Kevin Brand, military analyst working with the Council on Foreign Relations.
  • "There is also a diplomatic issue here, as the agreement to sell sensitive technology to a country implies a wider alignment of a range of political issues, and that is why the US is looking to isolate Russia following on from the events in Ukraine and beyond," said Charles Forrester, senior defense industry analyst at Jane's by IHS Markit.
"India places top priority on ties with Russia. In today's fast-changing world, our relationship assumes heightened importance.”
— Indian Prime Minister Narendra Modi to Vladimir Putin after signing the $5bn deal.

What to watch: Turkey, a NATO member, is one of the most significant potential buyers of the S-400, which would be difficult to integrate into NATO’s defense system. "The worst-case scenario,” Brand says, “is that there might be vulnerabilities that could be exploited by a potential adversary.”

Go deeper: Read the full Al Jazeera report.

Go deeper

1 hour ago - Health

Ex-FDA head: U.S. will "definitely" see 200,000 to 300,000 virus deaths in 2020

Former FDA commissioner Scott Gottlieb said on CBS News' "Face the Nation" that the coronavirus death toll in the U.S. will be "definitely" somewhere between 200,000 and 300,000 by the end of 2020.

Why it matters: "Whether we're closer to 200,000 or closer to 300,000 depends on what we do now and how it evolves," Gottlieb warned on Sunday as the U.S. surpassed five million confirmed coronavirus cases.

Mnuchin says Trump executive orders were cleared by Justice Department

Treasury Secretary Steven Mnuchin insisted on "Fox News Sunday" that President Trump's executive orders on coronavirus aid were cleared by the Justice Department's Office of Legal Counsel, and said that Democrats are going to "have a lot of explaining to do" if they choose to challenge them in court.

Why it matters: Democrats and even some Republicans have criticized Trump's decision to circumvent Congress to extend unemployment benefits as executive overreach, given that the Constitution gives Congress power to appropriate spending.

Updated 2 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Global: Total confirmed cases as of 11 a.m. ET: 19,680,042 — Total deaths: 727,777 — Total recoveries — 11,962,565Map.
  2. U.S.: Total confirmed cases as of 11 a.m. ET: 5,002,523 — Total deaths: 162,455 — Total recoveries: 1,643,118 — Total tests: 61,080,587Map.
  3. Politics: Nancy Pelosi says states don't have the funds to comply with Trump's executive order on employment — Trump adviser Larry Kudlow says he regrets suggesting the benefits could only be extended by Congress.
  4. Public health: Fauci says chances are "not great" that COVID-19 vaccine will be 98% effective — Poll: 1 in 3 Americans would decline COVID-19 vaccine.
  5. Schools: Nine test positive at Georgia school where photo showing packed hallway went viral — How back-to-school is playing out in the South as coronavirus rages on — Princeton, Johns Hopkins, Howard to hold fall classes online.