The fiercest critics of the Hamas-Israel cease-fire are those some expected to be its greatest beneficiaries: the parents of captive Israeli soldier Gilad Shalit.

Having pursued a largely low-key campaign for the liberation of their son since he was abducted by Hamas-led gunmen two years ago, Noam and Aviva Shalit have reacted furiously to the exclusion of their son from the Egyptian-brokered Gaza truce.

On June 22, the Shalits filed a petition with Israel’s High Court of Justice demanding that one of the key components of the cease-fire — the easing of Palestinian movement across the Gaza border — be blocked until Israel committed to retrieving their son. A day later the court denied the Shalits’ petition.

In a slew of media interviews, the couple accused Israeli Prime Minister Ehud Olmert of potentially having destroyed any chance of getting the 21-year-old hostage back soon — or even ever. They published a recent handwritten letter in which he wrenchingly begs to be freed.

“Two long and hard years have passed since I was separated from you and had to live in captivity. I continue to suffer from health and emotional difficulties and suffer many periods of depression,” Shalit wrote.

His parents’ criticism has roiled Israelis and fueled debate about the efficacy of Israel’s cease-fire with Hamas.

A June 20 poll in the newspaper Yediot Achronot found that 78 percent of Israelis think the Gaza truce should have been conditioned on Shalit going free, while only 15 percent disagreed. Asked if they agreed with Noam Shalit’s assertions that his son had been “forsaken” by the state, 68 percent of respondents said yes and 24 percent said no.

The public’s outrage might seem surprising given the Olmert government’s repeated assurances that Shalit is integral to the truce, which began last week and appeared to be on the verge of collapse this week.

Hamas denies any direct linkage between the suspension of hostilities and Shalit.

“We separated Shalit and the truce,” said Ismail Haniyeh, the Hamas leader in Gaza and deposed Palestinian prime minister. “The Israelis and their leaders have so far undermined reaching a prisoner exchange because they are not accommodating the Palestinian demands.”

Hamas wants Israel to free hundreds of jailed Palestinian terrorists in exchange for Shalit. Israel has balked at some of the names on Hamas’ list, arguing that returning mass murderers to the West Bank or the Gaza Strip would be disastrous for the embattled, relatively moderate Palestinian Authority.

But in recent days Israeli officials have hinted that they could relax their criteria. Israel hopes for similar flexibility from Hamas, though it has shown no signs of that.

The ace up Israel’s sleeve is Rafah, the main terminal on the Gaza-Egypt border, which was shut by Cairo after Hamas seized control of Gaza a year ago. Israeli officials say Rafah will not reopen unless there is “significant progress” in efforts to free Shalit, though what this would constitute remains unclear.

Noam Shalit has argued that Rafah could provide a conduit for Hamas to spirit out his son to a location where he will never be found.

“We all remember what happened with Ron Arad, how he was handed from one group to another and eventually disappeared,” Noam Shalit said in one interview, referring to the Israeli airman who bailed out of a plane over Lebanon in 1986, was captured and then disappeared. Israeli intelligence believes Arad was captured by Lebanese Shiite militiamen and later transferred to Iran, where many suspect he was killed.

When they announced they were filing their court petition, the Shalits found surprise support from Tammy Arad, the normally reclusive wife of the missing Israeli air force navigator.

“Captivity is a terminal disease. The chances of retrieval are in your hands,” Tammy Arad wrote in an open letter to the court. “Do not take away Gilad’s hopes of returning to his family. Do not take away Aviva’s and Noam’s hopes of reuniting with Gilad, of holding him in their arms again.”

Israeli defense officials are doubtful about whether Hamas would want Gilad Shalit to be anywhere other than Gaza. Taking him out through the Egyptian Sinai would risk a clash between the Palestinians and Cairo.