Moscow is trying to play it cool, but its military moves hint at growing concern over NATO's newest member

• Finland's admission to NATO this month doubles the length of NATO's border with Russia.
• Russian leaders have downplayed the significance of their neighbor joining the alliance.
• But Moscow is making moves that indicate concern about NATO gaining new territory nearby.

Finland joining NATO has created an unwelcome prospect for Moscow: a potential adversary on Russia's sensitive northern border.