Ukraine’s defence minister asked Western nations on Tuesday to scale up drastically its supply of precision rocket systems, calling them a “game-changer” that could allow a counteroffensive against Russian invaders. The United States since mid-June has delivered eight units of the M142 High Mobility Artillery Rocket System, or Himars, which can precisely strike targets within 80 kilometers (50 miles) using the ammunition that has been provided, with plans for four more. “They can shoot and scoot.” Defence and security analyst Professor Michael Clarke explains how important the HIMAR systems ar…