To urge a fourth round of warfare against Hamas is no easy matter, least of all at a moment when Israeli decision-makers were surprised to learn of an unanticipated fiscal gap of 3.6 percent between state revenue and expenditures. And wars are costly, not only in treasure but in lives.

However, questions about the timing of a fourth round with Hamas must not blind us to the need for it. Only another such round can possibly bring the group to the conclusion the Arab states reached after four rounds of war with the Jewish state in 1948, 1956, 1967 and 1973—that the pain to be suffered is so great and the chance of eliminating the Jewish state so slim as to render further violence pointless.

This realization on the part of the Arab states did not stem from a change of heart regarding Israel. In the most recent Pew poll, the most reliable survey of public opinion in the Middle East, the Egyptian public ranked as the most hostile public towards Israel in the Arab world.

Yet this hostility has not translated into Egyptian war-making against Israel since 1973. Memories of the pain and sacrifice caused by Egypt’s wars against Israel remain so powerful that in the elections held in 2012 after the ouster of the Mubarak regime, only one of the 21 lists called in its campaign platform to prepare Egypt for hostilities against Israel. That party, “Tomorrow,” secured less than 1 percent of the popular vote, proving that pain trumps deeply felt ideological and religious hatred of Israel.

Hamas seems to be treading the same path the Arab states trod.

Contrary to the mantra among politicians and media people that “after every round, we return to the same point,” after every round of massive fighting, Hamas has reacted with the launching of fewer missiles over time.

The most telling was what occurred after the third round in 2014. Fifty missiles were launched during the ensuing three-and-a-half-year lull compared to more than 2,000 missiles launched between the Israeli withdrawal from Gaza in 2005 and the first massive round of fighting in the winter of 2008-09, which was an even shorter interval.

What Israel achieved against Hamas is what Gen. Doron Almog and other military thinkers call “accumulated deterrence.” Hamas was continuously more deterred even as it trained and became more lethal.

Hamas, which is ideologically committed to destroying the Jewish state, tested Minister of Defense Avigdor Lieberman’s mettle by launching, eight months ago, weekly “marches of return” and daily incendiary balloons. Hamas called his bluff, and the Netanyahu government did not go to war.

This paved the way for a careful strategy of extortion in which Hamas tries to inflict a minimum of violence for maximum dividends, staying just shy of the type of all-out war it assiduously tries to avoid. This strategy annuls “accumulated deterrence,” and the dividends Hamas reaps are used to continue the violence and improve the lethality of its troops. The $15 million in cash recently distributed to Hamas by the Qatari envoy, with Netanyahu’s permission, highlighted the effectiveness of this strategy.

This is a losing proposition that can only be changed by another massive round of fighting. The closer the intervals between wars with Israel, the greater the chance that Hamas will not only be deterred from warfare, but will experience the change of heart that affected the Arab states in the 1970s.

There is no good reason to delay the next inevitable round of fighting. Consider the arguments made against another massive round.

The focus on Iran was one of Netanyahu’s declared reasons for delaying another war with Hamas. This no longer makes sense, as the United States has taken major steps against Tehran. One can even argue that Israel’s weakness against Hamas goads Iran on rather than inhibits it.

There was hope that pressure from the Gazan public would force Hamas into a quid pro quo—that concessions granted to Hamas for the sake of peace would result in the group being tamed in the way the Palestinian Authority has been tamed, at least to a degree. Yet after every concession (the latest in the form of pure cash), Hamas responds not with peace, but with bolder and more violent efforts at the fence, including crossing it for the purpose of intelligence gathering, and, above all, more missile-launchings.

Rather than “accumulated deterrence,” which Israel achieved in the first three rounds, we are now in an extortion framework. We are seeing provocations increase, with Hamas and its allies launching more and more missiles over the past eight months. At the previous peak in May, a little more than a month after the “March of Return” campaign began, 200 missiles were launched over two days. Last week, 469 missiles were launched over the same period.

One of the greatest acts of political acumen in recent world history was to reward West Germany with the Marshall Plan, as opposed to the sort of punishment that was meted out to a far more benign Germany after World War I. But this was only a wise move after the total defeat of Nazi Germany.

There are many who want to avoid war and shower Gaza with economic aid before defeating Hamas. This would be an act of political delusion, not acumen.

Solomon, the wisest of men, said there is a time for war and a time for peace. Now, alas, is the time for war.

Professor Hillel Frisch is a professor of political studies and Middle East studies at Bar-Ilan University, and a senior research associate at the Begin-Sadat Center for Strategic Studies.

BESA Center Perspectives Papers are published through the generosity of the Greg Rosshandler Family