The US and the Arab States are trying to contain Iran through conventional means while Iran is trying to break that containment through 4 Gen Warfare. Iran has been waging a Proxy War against the US in Afghanistan and Iraq. Iran sponsors Hezbollah and Hamas to fight and tie down Israel.

This is like a micro-version of the Cold War

The US is doing a few things.
1) Arming Arab Governments
2) Supporting theCaspian Guard north of Iran
3) Military Presence in Iraq, Afghanistan and Persian Gulf
4) Supporting anti-Iranian militants inside and outside of Iran
5) Trade and Financial sanctions

To help the US mission, President Ahmadinejad is hell bent on destroying the Iranian economy by rationing gasoline and raising the inflation rate. The Iranians also invested too little money into their oil industry, so they face hard economic times ahead.

To beat the US containment strategy Iran supported insurgents and militias beyond their border. The Iranian-Syrian alliance expanded to give the Iranians greater mobility.
Iran backed
-Jaish al-Mahdi
and a larger number of small groups. They want to influence or unofficially “capture” large chunks of Lebanon, Iraq, and Palestine with these forces.

Iranian support for Shia Islamist militias like Hezbollah and JAM is obvious. Hezbollah is the most successful as it hollowed out the Lebanese state. Shia influence seems limited because the Iraqis are too nationalist and the rest of the Arab world is Sunni.

The Iranian support for the Sunni Muslim Brotherhood HAMAS is more interesting. They are willing to ally themselves with Sunni Islamists to counter their enemies (Israel in this case).

The Iranians are also trying to break containment by finding Left-wing allies. Iran and Venezuela are allied states. Chavez supplies passports for Iranians and has enabled Hezbollah and Hamas to set up a base of operations for South America. Iran may be running propaganda to gain support in Europe to block action against Iran.

The US, Israelis and Arabs have been upping the stakes in their own way. They now support Fatah in Palestine against Hamas. They also seem to be backing Iraqi and Afghan tribes to resist Iranian-backed militias to prevent Hezbollah-type movements from taking over.

And both sides continuing the bluffs and posturing. Syrian troops invaded and took over a segment of Lebanon. Iran shelled Kurdish Iraq with artillery earlier this month. Iran continues their nuclear programs.

The US Navy made a huge show of force in the Persian Gulf and leaked (deliberately or not) a hint of its plans to launch a massive first strike to destabalize Iran. Not to mention that Israeli just executed a still mysterious airstrike against Syria.

If the US was not in the region, Iran would be the natural hegemony.