It seems that some are concerned that Russia will supply a defensive system which would stop the war mongers from attempting to invade and destroy their country. The weapons system which are not proven as being effective , yet are making some countries military to question their own ability to "project force".

No-Fly Zone: Russia's Lethal S-400 Goes Global | The National Interest Blog

"The proliferation of weapons like the S-400 and its S-300 predecessor pose a serious challenge of U.S. and allied air power. Both weapons systems are highly mobile, networked and can protect vast areas. Effectively, weapons like the S-400 and S-300 make an entire region inaccessible to conventional non-stealthy combat aircraft.

As one senior U.S. Marine Corps aviator told me earlier in the year, the S-300 series is a deadly threat to everything except the most advanced stealth fighters and bombers. “A complete game changer for all fourth-gen aircraft [like the F-15, F-16 and F/A-18]. That thing is a beast and you don’t want to get near it,” he said. Only the Lockheed Martin F-22 Raptor, F-35 and Northrop Grumman B-2 Spirit stealth bomber would be able to operate inside areas protected by those weapons. But even those aircraft could be challenged if there were enough S-300 or S-400 batteries operating as part of an integrated air defense network."

The game changing, allegedly, system can create an area of non usage for the attacking countries which negate their, allegedly, integrated forces for subjugation.