President Barack Obama learned the hard way that drawing lines isn’t a game. Had he not announced on Aug. 20 of last year that the use of weapons of mass destruction by the Syrian regime would constitute the crossing of a red line, the US president would not be now forced to choose between the loss of US credibility and the erosion of his personal prestige, and an additional military entanglement in the Middle East and a crisis in relations with Russia.

True, setting a red line promises a fat front-page headline next to a flattering photo of a courageous leader. On the other hand, the speaker must take into account that red lines are seared deeply into our collective conscious and enjoy a long life span. One can assume that we will not hear Obama talking again about red lines in the near future.

The Syrian case proves that yesterday’s red line can turn into tomorrow's gray area. What’s more, after Obama himself blurred Syria’s chemical red line, why should Israel rely on him regarding Iran’s nuclear weapons? What value is there to a red line drawn by Obama vis-à-vis a nuclear weapons development program — as long as he refrains from punishing a dictator who killed 1,500 people using such weapons?

A year ago to the day, on Sept. 2, 2012, Prime Minister Benjamin Netanyahu complained that Tehran continues to develop its nuclear program because of the refusal of the “world,” meaning the United States, to draw “a clear red line” for Iran. Had he been speaking today, Netanyahu should have been asked: And if Obama had drawn “a clear red line” for Iran, would you have been reassured?