Emmanuel Macron and Theresa May were put in the crosshairs by their own parliaments Monday for failing to secure a UN mandate – or even a parliamentary debate – before ordering missile strikes against Syria.

British Prime Minister Theresa May faced criticism from numerous MPs for failing to seek parliamentary approval before attacking Syria on Saturday. Speaking before the Commons, with May sitting nearby, Labour leader Jeremy Corbyn "reminded" the prime minister that she is "accountable to this Parliament, not to the whims of the US President." Corbyn pointed out that May's "predecessor came to this House to seek authority for military action in Libya and in Syria in 2015, and the House had a vote over Iraq in 2003," adding that "we clearly need a War Powers Act in this country to transform a now broken convention into a legal obligation."

Corbyn said during his remarks on Monday:

There is no more serious issue than the life and death matters of military action. It is right that Parliament has the power to support or stop the Government from taking planned military action.

Noting that Parliament had previously "voted for and against military action," Labour member Yvette Cooper slammed May for not allowing MPs debate a potential strike. According to Cooper, May and her Cabinet have "rejected the entire principle of consulting, debating and voting in Parliament in advance of military action."

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In August 2013, Parliament voted 285-272 against taking military action to deter alleged chemical weapon use by President Bashar Assad. The motion stipulated that UK forces would intervene only if UN investigators concluded that Syrian forces had carried out chemical attacks. At the time, then-Defense Secretary Philip Hammond said that he was "disappointed" with the vote, and worried that it would harm Britain's "special relationship" with Washington.

In sharp contrast to 2013, May did not allow Parliament to debate a potential strike against Syria – and did not wait for a proper UN investigation before ordering the missile attack. May has been criticized over the last week for not addressing concerns and questions put forward by Parliament, essentially bypassing the democratic mechanisms which the West often flaunts and 'promotes' abroad.

France's National Assembly also met on Monday to debate the strikes – and many of the assembly members did not mince their words while expressing their displeasure at President Emmanuel Macron's unilateral decision to attack Syria.

Jean-Luc Mélenchon, of the far-left France Unbowed, denounced France's participation in the strikes. Noting the absence of a UN mandate, he said the missile strikes were conducted "without evidence" of the Syrian government's culpability in the April 7 gas attack in eastern Ghouta. Mélenchon went on to lambast Macron for not consulting with France's EU partners before committing to an attack, calling the entire episode a blow to French diplomacy.

Mélenchon had earlier said that the strikes were carried out at the behest of Washington.

"This is a North American revenge adventure, an irresponsible escalation. France deserves better than this role. It must be the force of international order and peace," he wrote on Twitter shortly after Saturday's attack.

1/2 Les frappes contre la #Syrie se font sans preuve, sans mandat de l'ONU et contre elle, sans accord européen et sans vote du Parlement français. Et cela sans aucune perspective politique en Syrie. — Jean-Luc Mélenchon (@JLMelenchon) April 14, 2018

In an interview on French television, Mélenchon said that France was "not in independent situation which would allow us to have a possible role of mediation."

José Évrard, from Marine Le Pen's right-wing National Front, condemned Macron's decision to bomb Syria, describing it as an illegal action against a sovereign nation. He said that Macron was following in the footsteps of former US Presidents Clinton, Bush and Obama, who bombed Yugoslavia, Iraq and Libya using similar, dubious humanitarian justifications.

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Évrard also mocked Macron's claim that he had irrefutable evidence of Assad's complicity in the Douma gas attack, noting that the French apparently "consulted with social networks" to reach its irrefutable conclusion.

Christian Jacob, the leader of the Republicans in the National Assembly, said it was outrageous that Macron had not sought parliamentary approval for the strike, adding that the situation resembled the weapons of mass destruction hysteria in the run-up to the 2003 invasion of Iraq.

Florian Philippot, the leader of Les Patriotes, had previously pointed out the similarities to the prelude of the ill-fated Iraq War:

These irresponsible actions by President Macron who has reduced our country to the role of subordinate partner to the Americans, should be condemned, as they jeopardize world peace and, apparently, contradict our interests. The French people […] must rise up against this belligerent action by President Macron, who is becoming more and more to Donald Trump what Tony Blair was to George W. Bush.

The Assembly's suggestions that Macron had received external pressure to participate in the missile strike couldn't have come at a worse time. Prior to Monday's debate, the French president had given a speech in which he outlined his belief in "European sovereignty."

"Sovereign Europe is a Europe which protects people from huge risks, huge transformations, be it information risk or tax risk. This is a Europe, which bears our continent's ambitions and allows it to bear our values," Macron said, adding that France "will move forward with those who want to move forward. And those who doesn't follow us, will have to accept being on this Europe's sidelines."