In a speech to the United Nations Security Council, Ukrainian President Volodymyr Zelenskyy pleaded for action against Russia, citing grave "war crimes".

Afterward, former Bush speechwriter Marc Thiessen told Fox News that there is not much the United Nations is able to do because nearly half of its security council's permanent membership – the states with veto power -- are complicit in "crimes against humanity."

On "The Story", host Martha MacCallum referenced the Biden administration's careful language on war crimes after National Security Advisor Jake Sullivan declined to label Kremlin assaults on civilians "genocide."

"We have seen atrocities, we have seen war crimes, we have not yet seen a level of systematic deprivation of life of the Ukrainian people to rise to the level of genocide," Sullivan, a former Hillary Clinton adviser, had said.

Thiessen said it is difficult to watch footage of the civilian casualties, saying that such crimes are indeed "prosecutable" but the U.N.'s power is neutered.

"[G]enocide, crimes against humanity, war crimes, whatever you want to call it, these are atrocities, and they're prosecutable," he said.

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Zelenskyy speaks to UNSC

Zelenskyy speaks to UNSC ((AP Photo/John Minchillo))

"The problem is that the UN is completely incapable of addressing these atrocities for one simple reason: 40% of its voting members are actively engaged in genocide and crimes against humanity."

The United States, France, Russia, China and United Kingdom are the five permanent members of the council, who can all veto resolutions, while several other rotating and elected members include Gabon, the UAE, Ireland, India and Ghana.

"In China – [a] veto wielding member -- they have over a million Uyghurs in concentration camps in something that the United States has declared is genocide," he said.

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United States Ambassador to the United Nations nominee Linda Thomas-Greenfield testifies during for her confirmation hearing.

Biden's UN Ambassador Linda Thomas-Greenfield.

"And now in Russia, you have a leader who is engaging in the massacre of civilians in Ukraine – that is at bare minimum a war crime, and possibly genocide. They're not going to be able to address it."

Thiessen compared Russia's treatment of Ukrainian civilians to the 1995 Srebenica genocide in Yugoslavia, which spurred the U.N. to form an international criminal tribunal to prosecute the culprits, adding that Russia and China could veto the creation of a Ukraine-centric forum.

"That's why Zelenskyy said kick Russia off the Security Council or disband yourself. And he's absolutely right," Thiessen said.