Tensions between Russia and the West Hitting a new peak.

Tensions between Russia and the West are hitting a new peak. And in this face-off, Moscow has an extraordinary piece of leverage: a super-sophisticated, bomber-killing missile that it once threatened to sell to Iran.

Last week, Reuters first reported Russia was preparing an oil-for-goods deal with Iran worth up to $20 billion.

 An unnamed Iranian official told the news service that the barter would include Russian weapons. And that was before further signs of Russia’s shadow invasion of Ukraine emerged Monday, when crowds spontaneously appeared in three major eastern cities to welcome the troops amassed over the border.

 The Daily Beast reported that associates of Viktor Yanukovych, the deposed and Kremlin-friendly Ukrainian president, were meeting with pro-Russian activists. 

The S-300

One keen-eyed photographer captured a man wearing a Russian Airborne forces tee-shirt at one of The trade between Moscow and Tehran would alleviate the economic pressure on Iran that the White House has said helped bring the Islamic Republic to the bargaining table. It may even sink the talks President Obama is hoping will persuade Iran to defang its nuclear program.

If those talks fail, then Russia has the leverage to equip Iran with the missile that could defend its centrifuges and reactors from allied air strikes, the S-300.

The S-300 has long been Moscow’s top-of-the-line air defense system. The current model is comparable to U.S. Patriot missile batteries. The S-300 deploys sophisticated radars, launch vehicles and missiles to shoot aircraft and even ballistic missiles out of the sky.

 Russia has also threatened to sell the system to Syria, whose hapless air force was hacked by Israel in 2007, rendering its anti-aircraft defenses useless when Israel bombed the al-Kibar nuclear facility.