Syria is helping foreign fighters and terrorists - and their supplies - slither across the 600-mile border into Iraq. In other words, Damascus is supporting the killing of American and Coalition soldiers and civilians - like the five Marines lost along the border last Saturday.

We must make Syria pay a price for this - and make it stop.

Even Syria's defenders can only claim it's merely turning a blind eye to the bad guys. But U.S. military officials say that Damascus is, in fact, facilitating the thugs' movement and supplying them as well. Some believe that these foreign militants, including members of the deadly Shi'a terrorist group, Hezbollah, are instigating a lot of the troublemaking in Iraq right now.

Osama bin Laden has urged jihadists to travel to Iraq to fight the infidels, and as many as 3,000 foreign radicals may have already entered the country from as far away as Sudan and Chechnya. Up to 300 Syrians are in Coalition custody.

It's unclear whether Syrian President Bashar Assad has directed the aiding of the transiting terrorists. Assad says there's little he can do, because of strong cross-border tribal connections and the vastness of the Iraqi desert.

Gen. Richard Myers, the chairman of the Joint Chiefs of Staff, isn't buying it: "We know that the pathway into Iraq for many foreign forces is through Syria," he said this week. "It's a fact. We know it. The Syrians know it."

Syria won't mend its ways on its own. Assad's rusting, socialist Ba'athist regime is scared to death of having a shiny, new democracy right next door. The Syrian economy is in terribly bad shape (20 percent unemployment) and young people, who are fed up with the lack of reform, are pressuring the regime.

A democratic Iraq could send a tidal wave of freedom crashing over Syrian borders, drowning the hapless regime. The Iranian mullahs, Iraq's eastern neighbor, are shaking in their boots as well. In fact, the Syrians and the Iranian have deepened their cooperation of late just because they fear the effects of a democracy in the neighborhood.

Even beyond its troublemaking in Iraq, Syria is a problem on other fronts:

• It's a major state sponsor of terrorism, including Hezbollah, Hamas, Palestinian Islamic Jihad, the Popular Front for the Liberation of Palestine and the Popular Front for the Liberation of Palestine-General Command. These groups are blocking any solution to the Israeli-Palestinian peace process through their acts of terror. All of them maintain offices, training camps and other facilities on Syrian soil. They also operate in parts of Lebanon occupied by the Syrian military and security forces and get funding and logistical support, including weapons, from Iran via Syria.
• Damascus has continuously occupied parts of Lebanon since 1976. Today, more than 20,000 Syrian troops are there, influencing the Lebanese government and undermining its political independence.

Many have called for Syria to completely pull out of Lebanon, but keeping troops on Israel's northern border is just too good for Damascus to pass up.

As a result, Israeli's northern border and much of southern Lebanon is crawling with Hezbollah, Iranian Revolutionary Guards and other terrorists.

• Syria is still developing biological and chemical weapons, including the nerve agent VX and sarin. It also has short- and medium-range ballistic missiles capable of striking Israel with these weapons. Damascus may also have nuclear aspirations. (Al Qaeda-linked terrorists were arrested in Jordan coming in from Syria last weekend with chemical-weapon bomb-making material.)

It's time to put some heat on Syria:

Implement the Syrian Accountability Act: The Syrian Accountability (and Lebanese Sovereignty Restoration) Act, signed into law in December, lets President Bush impose sanctions on Syria, including prohibiting the sale of U.S. products and investment in Syria and restricting the travel of Syrian diplomats here.

Then increase the pressure: Call for Syrian withdrawal from Lebanon in the Security Council. Keep the Syria-Iraq oil pipeline closed. Encourage other major trading partners such as Turkey and Italy to limit commerce. Put more Iraqi forces on the border to prevent terrorist infiltration.

If terrorist camps along the Syrian-Iraqi border can be identified, we should consider military strikes.

In the past, Syria has done the right thing. It supported the first Gulf War with 20,000 troops and did some good turns against al Qaeda in the early days after 9/11. But Syria is clearly bucking to replace Iraq in the Axis of Evil. It's time to remind Damascus of the fate of that Ba'athist regime.

Heritage Foundation Senior Fellow Peter Brookes spent some of his days at the CIA working on Central Asian issues. E-mail: [email protected] .