Two Russian S-400 air defense systems on the back of trucks are parked in a snowy field with some trees around them.
S-400 defense systems, sent by Russia, at the Brestsky training ground near Brest, Belarus.
  • Russia's air defenses are being stretched, forcing it to choose where to send protection.
  • Experts say Ukraine's increased attacks on Russia have exposed and created gaps in its coverage.
  • Russia has long had the upper hand with defenses, but Ukraine is finding new opportunities.

Russia's air defenses are being stretched, putting the country in a position where it has to decide what to protect.