Last week, the Syria Campaign, a global advocacy group pressing for a peaceful and democratic future for the country, published a report accusing the United Nations of being "in serious breach of the humanitarian principles of impartiality, independence and neutrality".

Secretary-General Ban Ki-moon's spokesman has dismissed the report, but the UN would be wise to heed its findings, which are backed by more than 50 humanitarian, human rights and civil society groups in Syria.

The findings are based partly on interviews with current and former UN officials. Roger Hearn, former head of the UN agency for Palestinian refugees in Damascus, said: "There has been a systematic failure in the UN-led response. Rather than basing its response on need, it has developed into a billion-dollar response programme that is largely controlled by the regime and its proxies."

The findings are supported by statistics and reports from UN agencies, such as the World Food Programme and the Office for the Coordination of Humanitarian Affairs (OCHA).

Sieges as a weapon of war

"By choosing to prioritise cooperation with the Syrian government at all costs," the UN has given Damascus an "effective veto over aid deliveries to areas outside of government control, enabling its use of sieges as a weapon of war," the Syria Campaign said. "This has contributed to the deaths of thousands of civilians."

The UN cannot credibly refute claims of its subservience to the Syrian regime, because it has made no secret of the extent to which it seeks and relies on the regime's consent to perform its duties.

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A March report by OCHA said that UN agencies were "simply not willing to jeopardise their operations in Syria by taking a tougher stance with the government". Prophetically, OCHA said that this "will surely be scrutinised unfavourably at a later point".

As of the end of May 452,700 Syrians were besieged by the regime, representing more than three-quarters of the total number under siege.

Most recently, UN special envoy Staffan de Mistura has backtracked on airdropping humanitarian aid.

In May, he said the UN would use airdrops if access to areas besieged by the regime did not improve by June 1. This was in line with an agreement earlier that month by more than 20 countries at a meeting co-chaired by Russia and the United States.

Most importantly, De Mistura did not rule out overriding regime objections.

Airdrops

He reiterated his position on June 3, but six days later said: "We need government permission. That is obvious."

Except that it is not obvious at all. As of last month, the World Food Programme had made 35 airdrops to the town of Deir Az-Zor, which is besieged by the Islamic State of Iraq and the Levant (ISIL, also known as ISIS), without seeking the group's consent.

The UN would gawk at the idea of doing so, so why does it readily accept seeking the permission of the regime, which is by far the largest besieger of Syrians?

According to the UN itself, as of the end of May 452,700 Syrians were besieged by the regime, representing more than three-quarters of the total number under siege.

It is perverse for the UN to seek the regime's permission to alleviate sieges that have long been one of its primary weapons of war.

This only strengthens that weapon in the absence of sanctions for non-compliance, because as the Syria Campaign says - citing World Food Programme statistics - "the UN has allowed the Syrian government to direct aid from Damascus almost exclusively into its territories".

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It is even more perverse to still expect regime cooperation given its track record. According to the UN itself, almost 90 percent of its requests for aid deliveries in 2015 were either ignored or denied.

"Such inaction is simply unacceptable" for a UN member state and signatory of the UN charter, Stephen O'Brien, the under secretary-general for humanitarian affairs and emergency relief, told the Security Council in January 2016.

One UN official said that the requests were already "censored at the agency level", meaning that the number was kept low so as not to "annoy" the authorities.

Yet as of this month, De Mistura says the regime's promises should be taken at face value. It is farcical to rely on Damascus' permission for airdrops to circumvent its non-compliance regarding land deliveries.

The risk of UN aircraft being shot down is cited as a reason for needing consent. However, it is inconceivable that the regime and its ally Russia would risk the international outrage, and military and political repercussions, of shooting down UN aircraft delivering humanitarian aid because the regime is refusing land access.

UN kowtowing goes beyond the issue of humanitarian aid.

Chemical weapons

UN kowtowing goes beyond the issue of humanitarian aid. In 2013, it shamefully accepted the regime's demand that for investigators to be allowed into Syria to probe the use of chemical weapons, blame could not be assigned - not a demand that would be made by an innocent party.

The scope was thus limited to whether chemical weapons had been used, not who used them. With this lack of accountability, the presence of UN investigators has not prevented more chemical attacks.

Another example of the UN's subservience is its continued refusal to address the fate of Syrian President Bashar al-Assad in the peace process. This may look impartial on the surface, but it has only served to keep him in power.

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This is not simply a result of being hamstrung by opposing sides. In December 2015, Ban said: "It is unacceptable that the whole Syrian crisis and the solution to the crisis have to be dependent on the fate of one man."

What is unacceptable is the attempt to sweep Assad's central role in the conflict under the carpet, particularly when the UN itself has documented his regime’s war crimes and crimes against humanity, including "extermination", and when senior UN officials (including Paulo Sergio Pinheiro, head of the commission investigating war crimes in Syria, and former human rights chief Navi Pillay) have highlighted the regime's primary culpability.

The UN cannot in good conscience highlight the blood on Assad's hands while willingly shaking them, and expect that this will bring peace or relief to the Syrian people.

Sharif Nashashibi is an award-winning journalist and analyst on Arab affairs.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.