These attacks abroad are really a sign of weakness and not strength

Since 1979, researchers have identified above 200 plots linked to Iran around the world, but there has been a sharp rise in recent years

- Jason Burke

Iran's involvement in clandestine violence and espionage overseas takes multiple forms - but all have a single aim: to win advantage for Tehran by striking unexpectedly at the "soft underbelly" of enemies.

It's a strategy dating back to the 1979 revolution, and is rooted in a pragmatic if regretful assessment of Iran's continuing weakness on the conventional battlefield.

Australian authorities have not revealed exactly what convinced them that Iran was behind a series of recent antisemitic attacks, but the charge is plausible, experts say.

"We don't know the full details but the Australians wouldn't [publicly blame Iran] unless they were pretty confident," said Matthew Redhead, an expert in state threats and intelligence at the Royal United Services Institute. "Iran sees this as a cheap way of fighting an undeclared war against its opponents and of rallying audiences it wants to impress in the Middle East... they don't have the resources to fight any other way. There is a long history here."

One of Iran's goals is to distract enemies and so divert any concerted direct attack. Until recently, it could be argued that the strategy was relatively successful, fending off foes at limited cost.

Yet it failed this summer. The damage done to Iran's nuclear programme in the two-week war with Israel and the US in June may be unclear, but few doubt Tehran came off worst in the hostilities.

Iran promised "everlasting consequences" for the US - at a time and place of its choosing.