ATACMS missiles could push back Russia's lethal helicopter force, but Ukraine will need perfect timing to pull it off

• The US looks set to send Ukraine the Army Tactical Missile System, which Kyiv has long sought.
• ATACMS has longer range than Ukraine's other missiles, allowing it to hit valuable Russian targets.
• But using it effectively will require accurate intelligence and precise targeting, experts say.

The US appears is set to send Ukraine the MGM-140 Army Tactical Missile System, a short-range ballistic missile that Kyiv has long sought and Washington has long declined to provide.