Bashar al-Assad's regime has been shadow boxing with the prospect of a U.S.-led attack for years. That one is now being threatened must seem to Assad like proof he was right all along.

In many conversations with Syrian officials over the years, it was a common refrain after Iraq's Saddam Hussein was removed in the 2003 invasion that Assad might be next.

But these officials always insisted that should the U.S. strike, Damascus would be different. It would never succumb to foreign powers, or become a Western "puppet" as others have, they said. Not when it defines itself as a wellspring of resistance to the West and Israel.

So now, as Barack Obama threatens some kind of military strike in response to Syria's apparent use of chemical weapons last week, it is hardly a surprise that Damascus is promising to fight back in some unspecified way.

"We have the means to defend ourselves and we will surprise everyone," Walid Muallem, Syria's foreign minister, said in a news conference this week. "We will defend ourselves using all means available. I don't want to say more than that."

Syrian refugees sit at a new refugee camp in the outskirts of the city of Arbil in Iraq's Kurdistan region. Millions have fled the country in the past two years. (Azad Lashkari / Reuters)

It is worth noting, though, that save for the past two and a half years of a brutal suppression of opposing rebels — and its own citizens — Syria has not engaged in any kind of serious combat for many years despite its sizeable military.

It had only rarely even embarked on a skirmish — even when attacked by Israeli warplanes in 2007 (on what Israel suspected was a nuclear facility). Despite its vigorous anti-Israel rhetoric, Syria failed to respond.

But with a long history of enmity against the U.S., Syria will almost certainly feel compelled to strike back, if only symbolically.

"The Syrians may calculate that they can launch a limited attack, just like the Americans are calculating that they can launch a limited attack," explains Malcolm Chalmers, of the RUSI Institute for Defence and Security in London.

"But attacks are really limited if the other guy doesn't respond. Once the other guy responds … you get into a ladder of escalation, which is inherently unpredictable."

In short, a chain reaction. Which in the combustible Middle East could quickly destabilize an entire region.

Has allies

But should it choose to strike back, Syria needn't do it alone. It has a short but potent list of allies, including Russia and Iran, who have also warned repeatedly against a Western military attack.

They're not likely to enter a conflict if the U.S. strike is as specific and directed as some have suggested.

Assad may have allies, but does Barack Obama? British PM David Cameron lost a vote in Parliament on Thursday that would have authorized the U.K. to take action against Syria for the use of chemical agents. (Reuters)

But Syria is also close to Hezbollah, the well-armed Shia group that fought a conflict with Israel in 2006. The question many are asking today is could that group seek revenge on behalf of Syria by engaging Israel again?

Lebanese observers doubt it. Hezbollah is in an awkward position in Lebanon given that its men have openly fought alongside Syrian troops against the mainly Sunni rebels taking on Assad.

Lebanon is also divided between pro- and anti-Assad factions, and that tension, which recently evolved to include large bombs apparently aimed at each other, threatens the country's stability.

But having aligned itself with the Syrian regime, Hezbollah may ultimately feel compelled to act.

All this suggests that the risks of even a pinpoint, short-lived U.S. strike may not be much different from those that prevented the West from intervening at any earlier point in a conflict that has killed over 100,000 Syrians, by UN estimates, and forced millions to flee.

Now these risks would also include the possibility of civilian casualties at the hands of Western powers, even elsewhere in the region, not to mention the possibility of aiding those anti-Assad fighters with an Islamist agenda, some affiliated with al-Qaeda, which would subvert the original call for freedom and justice by those initial Syrian protesters.

The U.S. now appears adamant that a chemical weapons attack cannot go unpunished, and that a strong message must be sent, and as quickly as possible.

But can the U.S. mete out that punishment for this one instance and expect nothing to change? Should it?

Ultimately the test is simple: Would the benefits of sending such a message outweigh the many risks?

At the moment it seems that only one country will have to come up with that answer. While Assad's regime waits for what it has long felt was inevitable.