This is despite the fact that the last raid a few months ago on a military installation near Damascus caused a huge fire and an explosion big enough to register on the Richter scale, he said. Israel has traditionally been regarded as a sworn enemy of Syria, making the lack of response even more marked.
Defectors from the Syrian military, particularly the air force, also say that the country's air defense systems aren't as good as they're made out to be, Maher said, although their assessments have to be taken with a pinch of salt since they aren't impartial.
At the same time, he said, Syria's government realizes that while the United States has been pushed toward action by its suspected chemical weapons attack, any reprisal against American forces would inevitably escalate the conflict.
This would be inconvenient because it comes at a time when the Syrian military has been making key gains against the rebel forces, for example in the strategically important Homs region, he said, and is also committed to operations elsewhere, for example protecting Latakia, an Alawite stronghold in the north.
President Barack Obama has said there will be no U.S. "boots on the ground" in Syria. He has also ruled out any open-ended commitment and shown no enthusiasm for setting up a no-fly zone.
If the forces involved in any foreign intervention are out of reach, another potential threat is that Syria could make use of what analysts believe is a large stockpile of chemical weapons, or launch terror attacks through its proxies.
Syria is believed to have the capability to deliver chemical weapons agents by a variety of methods, including ballistic missiles, according to IHS Jane's.
The Syrian military's apparent chemical weapons attack on a rebel stronghold outside Damascus on August 21 has "demonstrated a propensity to use it against its own," said Maher.
But he believes al-Assad's calculation will be "that if he doesn't use these weapons of mass destruction he will be basically allowed to get on with it," and so continue the conventional warfare that has already seen more than 100,000 people killed nationwide without concerted international action.
As for proxy attacks, Syria's civil war is already spilling over the borders of its neighbors in the form of bombings and refugees and is widely seen as a proxy war among different regional powers.
Juan Cole, a professor of Middle East history at the University of Michigan, said al-Assad's government might try to strike back by targeting American military, diplomatic or commercial interests in the Middle East, perhaps employing its allies in the Lebanese militia Hezbollah -- which has a long and bloody track record targeting Americans during Lebanon's long civil war.
"If Washington bombs things in Syria, I wouldn't want to be an American in Beirut within reaching distance of Hezbollah," he said. "You could see a return to 1980s types of things happening, when our embassy was blown up in Beirut and our CIA station chief was kidnapped and killed in the woods."
Ex-Navy planner Chris Harmer warns of the danger that Syrian chemical weapons could be passed to Hezbollah in the wake of any strike. "The worst possible outcome for the United States and the West in general is for these chemical weapons to transfer from Assad to Hezbollah," he said.
Hezbollah could also decide to strike back on its own behalf if its key interests are hit in Syria, said Harmer.
"If Hezbollah believes that this is really affecting the Assad regime's ability to stay in power, you could see Hezbollah do any one of a number of things," he said. "They could fire some rockets at Israel -- they may do that anyway. They could engage in asymmetrical warfare terrorist attacks abroad, and theoretically if there are severe attacks and Hezbollah is really threatened, theoretically they could decide to target Western interests, most likely in the region."
However, Maher argues that since Hezbollah has already contributed thousands of fighters on the ground in Syria, its capacity to act elsewhere could be limited.
Some worry that a U.S.-led strike on Syria would increase the likelihood of cyberattacks.
The Syrian Electronic Army, a group of hackers which backs the al-Assad regime, took The New York Times offline for a period this week in what experts said was a significant escalation of its operations. It had previously targeted other U.S. and European media organizations, including CNN.com.
Helmi Noman, a researcher at the Munk School of Global Affairs' Citizen Lab at the University of Toronto, predicts these hackers will look for more chances to exploit weaknesses in America's cybergrids.
But U.S. agencies will be looking to counter the Syrian Electronic Army's efforts, which so far have caused embarrassment rather than major damage.
"It's clearly a nuisance, but its tactics aren't all that sophisticated," a U.S. official told CNN. "And while the regime probably welcomes its efforts, Damascus isn't necessarily calling the shots."
Of course, military planners for the United States and its allies are well aware of the threat that Syria could pose in the event of any foreign intervention and will be making preparations.