Beware: The Gaza Strip may be only the first domino to fall this summer in Iran and Syria's push to establish an arc of influence across the Middle East, stretching from the Persian Gulf to the Eastern Mediterranean. Lebanon, already teetering on the brink of instability, could easily be next.

The United States, Europe and Arab states need to act immediately to shore up the embattled pro-Western, democratic Lebanese government. Syria, which occupied Lebanon from 1976 to 2005, and Iran, which controls Islamist-terrorist Hezbollah, with help from al Qaeda, already have Lebanon under siege.

Last week saw another assassination of a leading anti-Syrian Lebanese figure - parliamentarian Walid Eido, killed with nine others in a horrific Beirut car bombing.

Eido was an outspoken member of the anti-Damascus "March 14th" movement, a key organization in effecting Syria's 2005 retreat from Lebanon. Eido is at least the seventh Lebanese anti-Syrian luminary assassinated since February 2005, when Damascus allegedly offed former Prime Minister Rafik Hariri in a car bombing. As always, the Syrian regime denies any involvement.

Some observers suggest the political killings are (among other things) an ongoing plot to undo the March 14th movement's razor-thin majority in the parliament. Following Eido's death, it only holds 68 out of 128 seats in the parliament.

While Prime Minister Fouad Siniora's government is calling for a special election on August 5 to replace the murdered lawmakers - including Pierre Gemayel, who was gunned down last November - Emile Lahoud, who occupies the Lebanese presidency thanks to Syrian sponsorship, continues to oppose a by-election.

Eido's killing was also the sixth, and biggest, bombing in or around Lebanon's capital, Beirut, in the last month - and came just days after the United Nations finally established a special court to try Hariri murder suspects - almost all of whom are assuredly Syrian.

In a bid to prevent any Lebanese role in the U.N. tribunal, Syria, Iran and their pawns have ensured political gridlock in Beirut since last November. Pro-Syrian protestors, led by Hezbollah, have besieged Siniora's government with protests, both physical and political, attempting to topple it.

Hezbollah, buoyed by its survival in last summer's war with Israel, has been pressing for a new government - one that would guarantee it enough seats in the Cabinet to assure it a veto on any decision.

Meanwhile, Sunni militants - linked to al Qaeda as well as Syria - have been battling the Lebanese army since May. Fatah al-Islam is holding up in Nahr al Bared, a Palestinian refugee camp near Tripoli, Lebanon's second-largest city. The group threatens to take the conflict to some of the other 11 Palestinian refugee camps across Lebanon, home to as many 400,000 displaced persons, potentially lighting off a larger powder keg of violence in the country of 4 million.

In fact, early June already saw some fighting at Lebanon's largest refugee camp at Ain al Hilweh between another al Qaeda affiliate, Ansar al-Islam and the Lebanese army.

And Syria and Iran have re-armed Hezbollah since last summer's war, too - so Hassan Nasrallah's thugs are ready to go against either Israel or the Beirut government, if given the green light from their Tehran and Damascus masters.

Lebanon is clearly nearing a tipping point. The Siniora government may be able to hold out, fighting on multiple fronts, both politically and militarily, against determined foes sponsored by rogue states.

Or the joint efforts of al Qaeda, Hezbollah, splinter groups, Iran and Syria could bring the country to its knees, putting an end to the progress-albeit halting-Lebanon has made since throwing off the shackles of Syrian occupation.

If concerned outside powers don't bolster Lebanon's moderate forces against the Islamists, terrorists and the Tehran-Damascus axis, the odds are against the Siniora government surviving - especially in the aftermath of the Hamas victory to the south in Gaza.

States with a stake in Lebanon need to get on the stick - with a lot more than rhetoric - to prevent Lebanon from succumbing to Islamist/Syrian/Iranian aggression:

• An aircraft carrier on the Lebanese coast would remind Syria that it can't act with impunity. Why not make it French, signaling recently elected French President Nicolas Sarkozy's new foreign policy?
  
  
• Economic sanctions have a place, too - especially on Syria and Hezbollah's fund-raising in Europe.
  
  
• Also vital: Getting arms to the Lebanese army for crushing Fatah al Islam - and deterring Hezbollah from acting militarily against the central government.

The fall of Gaza to the most radical elements of Hamas has already emboldened Islamist and jihadist forces across the Middle East. Lebanon's fall would only add fuel to the fire - meaning a tougher road ahead in Iraq, Afghanistan and the War on Terror.

Peter Brookes is a senior fellow at The Heritage Foundation and the author of "A Devil's Triangle: Terrorism, WMD and Rogue States."