Syria changed its status two weeks ago: The regime in Damascus admitted that it had stockpiles of chemical weapons that were ready to be used. The switchover was done casually, in the shadow of that country's raging civil war. But it seems it deserves more attention than it has received.

The acknowledgment of the chemical weapons came from Syria's Foreign Ministry spokesman, Jihad Makdissi, who merely wanted to clarify that the regime didn't plan to slaughter its people using weapons of mass destruction. In this way, he inadvertently revealed his country's chemical capabilities. Syria will never use chemical weapons or any other nonconventional weapon against its own people, he said at a briefing to journalists. They would only be used against an external attack.

That was how he ended the chemical ambiguity that Syria had adopted since the 1970s; he hinted at the existence of biological weapons and, more importantly, made clear that Syria was sticking to its policy of "first use."

This clarification is of great importance since it establishes Syria's intention to use chemical weapons against an attacking army, even if the attack is carried out with conventional weapons. This is a significant innovation. Until now, it was assumed Syria's chemical weapons would be used only if it was attacked by weapons of mass destruction. Now it turns out that the Syrian army's plans include a chemical response to any outside aggression.

The Syrians began stockpiling chemical weapons in 1973, shortly before the Yom Kippur War. Since then, they have expanded the program, so their chemical weapons inventory is the most advanced in the Middle East, according to Western assessments. In the 1980s, the Syrians began developing chemical warheads for their ballistic missiles. These can cover every spot in Israel, as we all know.

Syria, like Israel, did not join the 1993 treaty banning the production, stockpiling and use of chemical weapons. Syria thus maintained ambiguity regarding its quantity and kinds of chemical weapons; it also maintained ambiguity about its policies.

In developing chemical weapons, the Syrians wanted to create a strategic balance against Israel's nuclear weapons. They developed the weapons as weapons of deterrence, not use. Even during the greatest wartime crises, presidents Hafez and Bashar Assad did not use their chemical weapons. They did not use them in the Yom Kippur War when the Israel Defense Forces approached Damascus, during the first Lebanon war when the Syrian army was routed in the Bekaa Valley, or when the Israel Air Force - according to foreign reports - attacked their nuclear reactor in 2007.

Indeed, the IDF viewed Syria's chemical weapons as a component in the deterrence between the two countries. The IDF's working assumption was that the Syrians would not make "first use" of chemical weapons but would respond with them if Israel attacked Syrian territory with weapons of mass destruction. All that has changed. The Syrians apparently have changed the rules of the game and the deterrence equation.

It's very possible that this has happened because of the pressure on the regime; it's in danger of being deposed. But that doesn't matter. The IDF must take into account that the Syrian army could use chemical weapons in response to an attack on Syrian territory - yet another good reason not to interfere in the events across the border.