On Tuesday morning, a grad rocket was fired from the Gaza Strip toward the Israeli city of Ashkelon. In response, Israel closed Gaza's commercial crossing and tightened the travel restrictions imposed on Gaza’s residents. The crossings are still closed this weekend, though not in the extreme exception of a medical emergency.

I cannot overstate the severity of having a rocket fired toward Ashkelon. Deliberate or indiscriminate, fire on civilian targets violates international humanitarian law and can be considered a war crime. Because the Hamas regime controls Gaza, it bears the responsibility for the shooting—as do those who actually fired the rocket.

The strict prohibition against deliberately harming civilians is exactly what similarly makes Israel’s response, which is also aimed at civilians, entirely unacceptable. That is the meaning of the ban on collective punishment: You may fight combatants, but you may not punish civilians for actions they did not commit.

Let there be no doubt: No security imperative compelled the travel restrictions. Erez Crossing remained open this week to Israelis for foreign nationals and even Palestinian residents with registered addresses in the West Bank. Meanwhile, people from Gaza were denied travel.

Israel's declaration this week, that the closure of Gaza's crossings to civilian movement is a response to rocket fire, signals a worrying regression to a policy that has been discredited according to any and all criteria—legal, moral, and utilitarian. The decision to block civilians from traveling also contradicts declarations made by top military officials, where distinguishing between combatants and civilians is the cornerstone of their Gaza policies.

Between 2007 and 2010, Israel openly instituted a policy that restricted the movement of goods and people in and out of Gaza, ostensibly in order to put pressure on the Hamas regime. As part of this policy, Israel closed the crossings in response to shootings; when the crossings were opened, they only allowed humanitarian goods to enter. In fact, the restrictions were so tight that Israel had to calculate the minimal caloric needs of Gaza’s residents in order to make sure that their restrictions would not cause malnutrition.

That policy failed in every possible way. The shortages actually strengthened the Hamas regime, which developed alternative and lucrative supply routes through the tunnels running under the Gaza-Egypt border. Travel restrictions intensified Gaza’s isolation from the rest of the world, preventing women from developing professionally, young adults from studying, and workers from making a living—to name a few.  And it increased the dependency that Gazans place on the Hamas regime and international aid. The restrictions also damaged Israel’s reputation abroad, where Israeli citizens, businesses, and government officials continue to bear the economic and diplomatic consequences of that harm.

As a result, beginning in the summer of 2010, top military and government officials announced that they would begin to distinguish between civilians and combatants and seek to encourage economic development in Gaza  based on the understanding that this would create the conditions for stability and, perhaps, even a different kind of relationship between Gazans and Israelis. In 2011, as part of the announcement of steps to expand civilian movement, the Defense Ministry official in charge of the crossings, Major General Eitan Dangot, declared: “We are committed to distinguishing between the population and terrorist activists.” Only a week ago, Dangot’s office announced that measures taken to increase the volume of goods entering Gaza in fact “increase revenues for the Palestinian Authority treasury, by collecting customs and other taxes,” as compared to goods coming through the tunnel—which Hamas taxes.

If that's the case, it is not clear why Hamas’ “punishment” for the rocket fire results in an increase in revenue from the taxes it collects on goods entering through the tunnels, which continue to remain open for business.

The real victims of this supposed punishment are the women who were supposed to travel to the West Bank for professional training; the daughter who waited months to receive permission to visit her ailing mother in the West Bank; the factory owner who planned to receive raw materials, so that his factory could operate and his employees would make a living.

These are the real people punished due to an illegal and ineffective policy. But we in Israel are also being punished, because this policy doesn’t just shape the future of Gaza’s residents—it also shapes the future of Israelis.