The Economist explains

What are HARM, the air-to-surface missiles destroying Russian air-defence radar?

America’s supply of the powerful weapons to Ukraine has given its air force a telling advantage

This US Navy photo released 01 April 2003 shows a High Speed Anti-Radiation Missile (HARM)that is positioned on an F/A-18C Hornet during night flight operations 31 March 2003,aboard USS Kitty Hawk (CV 63), in the Gulf. The HARM missile was first deployed aboard Kitty Hawk in January 1984. Kitty Hawk and her embarked Carrier Air Wing Five (CVW-5) are conducting combat missions in support of Operation Iraqi Freedom. AFP PHOTO/US NAVY/Todd FRANTOM (Photo by TODD FRANTOM / US NAVY / AFP)

ON AUGUST 19TH a senior Pentagon official confirmed what had previously only been hinted at: America is supplying Ukraine with High-speed Anti-Radiation Missiles (HARM). The missiles have been playing an important role in Ukraine’s spectacular offensive in Kharkiv province, as well as a separate attack in the south. Launched from an aircraft, HARM homes in on and destroys air-defence radar. The missiles represent a serious challenge to Russia. Even if not fired, the threat they pose can force radar operators to turn off their sets and lie low. Ukraine’s air force, as a result, may not quite fly with impunity, but it has greater freedom than before.

More from The Economist explains

Who are the Druze, the victims of a deadly strike on Israel?

The religious minority has often been caught up in regional crossfire in the Middle East

Myanmar’s rapidly changing civil war, in maps and charts

Ethnic militias and pro-democracy groups are scoring victories against the governing junta


Who will be Kamala Harris’s running-mate?

She is reportedly vetting a dozen options. These are the top three


Why have so few American presidents been from the West?

Kamala Harris’s nomination would be a milestone for the region

Why the Olympics still has a doping problem

Cheating with drugs has again become an organised affair

Why some Russian athletes will be eligible to compete at the Paris Olympics

Despite antipathy between the Russian government and the International Olympic Committee a handful will compete