The violence that has swept across Israel over the past week, ranging from rock-throwing to rioting to rockets, underscores the increasingly dangerous erosion that has taken place in the Jewish state’s deterrent posture.Simultaneously, Israel now finds itself under assault from both Hamas terrorists in Gaza and many of its own Arab citizens, each of whom is resorting to violence on a wide scale with what appears to be a sense of total impunity.And that is what makes it so critical for the government to move quickly and firmly to quell the turmoil.If allowed to continue unabated, the mayhem might not only spiral out of control, but is likely to cause lasting damage to Israel’s ability to deter Arabs and Palestinians from carrying out future attacks.Indeed, as of this writing, Palestinian terrorists in Gaza have fired over 110 rockets, mortars and explosive projectiles at Israel since last Wednesday – an average of nearly 20 a day. Despite increasingly bellicose warnings from Israel’s government, the perpetrators went ahead and expanded their range of targets to include Beersheba.Israel’s response has been remarkably tame, with most of the action limited to bombing empty buildings in Gaza in the middle of the night, when the likelihood of taking out terrorists is minimal, as even bad guys need to sleep.Israeli warnings and threats have been answered by additional barrages of rockets, forcing countless thousands of innocent civilians in the south to live under siege by the Palestinians.Meanwhile, from north to south, Israeli Arabs have taken to the streets and carried out increasingly brazen attacks, such as stoning vehicles near the Negev town of Omer, attacking police with firebombs in east Jerusalem and seeking to block Route 70 in the north.Buses have been stoned, synagogues attacked and drivers assaulted in their vehicles as the police largely failed to impose order.And that is precisely where deterrence, or the lack of it, comes into play. For if those launching the rockets or hurling the rocks knew that their actions would result in dire penalties, they would be less likely to engage in such malicious behavior.According to the US Department of Defense’s authoritative Dictionary of Military Terms, deterrence is defined as “the prevention from action by fear of the consequences. Deterrence,” it explains, “is a state of mind brought about by the existence of a credible threat of unacceptable counteraction.”Clearly, that “state of mind” does not exist among Hamas terrorists or Israeli Arab rioters, which signifies that Israel has failed to strike sufficient fear in the hearts of those who choose the path of violence.The key to effective deterrence is to make the cost of misbehaving so great that most sensible people will refrain from crossing whatever red lines are laid down. In other words, there has to be a credible threat backed by the potential use of force as well as the will to use it. And for this to work, it is essential to identify that which is truly important to one’s opponent, something they value – be it life, power or money – and then threaten to take it away.In the case of Hamas, wagging a finger at them and saying “shame on you,” as the government did last week, is hardly an effective means of conveying the message.Instead, steps such as declaring that any rocket attacks will immediately result in the targeted killing of Hamas leaders both in Gaza and abroad, as well as the destruction of Hamas’ governing institutions in the Strip, would create a simple and clear calculus of conflict.Vague and abstract warnings about “a forceful response” are simply insufficient. A direct and very public link needs to be made between cause and effect, between Hamas’ actions and the resulting consequences.And if that proves inadequate, then there is always the option of ratcheting it up a notch and declaring that the Hamas regime in Gaza will be toppled if the attacks do not cease.Similarly, in the case of Israeli Arabs who riot, assault motorists and assail police, the authorities need to make clear that unlike previous outbreaks, this one will be met with a firm hand, mass arrests and maximum jail sentences. Anything less than zero tolerance is simply an invitation to troublemakers to foment chaos.To be sure, deterrence is never foolproof and there is no such thing as perfect security. There will always be those who are seemingly willing to give up everything for the sake of their cause, however irrational it might be.But when practiced correctly, and with determination, deterrence can ultimately save lives by dissuading individuals or organizations from engaging in violent behavior.As Sun Tzu, the great Chinese military strategist, noted in The Art of War, “to win one hundred victories in one hundred battles is not the apex of skill. To subdue the enemy without fighting is the apex of skill.”By upping the ante, tossing aside weakness and indecision, and laying down some clear redlines, the government can contain the current outbreak of violence and reduce the chances of it recurring.And, most important of all, it can restore the country’s posture of deterrence, and put the fear of God into anyone thinking of raising a hand against the people of Israel.