Now that President Obama has made up his mind about taking America to war with yet another Muslim country, he wants Congress to get on board.

To his credit, he’s seeking congressional authorization, as required by the War Powers Act of 1973, but he has given every indication that he’ll invade Syria irrespective of approval by majorities in the House and the Senate.

Presidents have done it before, without congressional authorization, from Harry Truman to Ronald Reagan to Bill Clinton.

This would be a shame. Not only would it mean that the U.S. would be flouting, somewhat ostentatiously, international law, but it would also mean that this would be the eighth Muslim-majority country with which America has been at war during Obama’s term as president. Count them: Iraq, Afghanistan, Pakistan, Yemen, Mali, Libya, Somalia, and now Syria.

This weekend, the White House came courting to Congress, showing evidence and secret intelligence to make the case for military action. What was remarkably lacking, however, throughout all the pomp and circumstance, was any other tool in their intervention toolkit.

No talk about exhaustive diplomacy with all stakeholders involved.

No talk about violence prevention. 

No talk about the International Criminal Court. 

No talk about working with the U.N. Security Council. In fact, quite the opposite: as evidenced by Secretary Kerry’s speech on Friday and Obama’s speech on Saturday, an implicit dismissal of all of these options. In fact, Kerry directly dismissed the U.N.’s role and its Secretary General Ban Ki-Moon, as did the president.

This is unprecedented, especially for a Democratic White House. This also puts the president’s main argument – that the violation of international law, vis-à-vis chemical weapons usage, is the main pretext for invasion – in a precarious position.

Why, because the president, unless he gets clearance from the U.N. Security Council before/after he gets clearance (or not) from members of Congress, will also be in direct violation of international law.

That means that our president is going to war with another country’s president for violating international law while our president is fully prepared to violate international law. How’s that for international norm setting and standard bearing?

America must remember that, at present, there is no international legal justification for an attack on Syria. 

America would need a United Nations Security Council resolution, backing the invasion, which it has yet to secure. 

This is a clear double-standard and one that erodes the ethical fabric forged in 1945, within the United Nations Charter, and before, in the Kellogg-Briand Pact of 1928.

America should care about international law and justice, and we should use all necessary measures and mechanisms in place for such legal enforcement, to hold Assad – and possibly some of the rebel groups --accountable for crimes against humanity and war crimes.

We agree that there is no excuse for President Assad’s actions. If the Assad government is responsible for the hundreds dead from last week’s chemical weapons use, Assad will have violated international laws like the 1925 Geneva protocol prohibiting the use of biological and chemical weapons.

That still doesn’t allow America, or the UK, or France, to invade the country.

Syria’s lack of involvement, as a state party, in the 1972 Biological Weapons Convention and the 1993 Chemical Weapons Convention, also does not justify military intervention by the West.

No matter how egregious the violation, America must still work within the legal frameworks at the United Nations Security Council, lest we undermine them further by flouting their very existence. Failure to do so would not be a good legal precedent for an American president to set.

Secretary Kerry once agreed with this thinking, reaffirming, during his confirmation hearings in January 2013, “a U.N. resolution is a necessary ingredient to provide the legal basis for military action in an emergency”.

And while this crisis in Syria is undoubtedly an emergency, in light of the concern that the Assad government used chemical weapons on his people, we have had plenty of time – and tens of thousands of deaths – to make the legal case to the U.N. Security Council and to the US Congress, something the Obama administration has failed to do.

If the administration wants to avoid undermining almost a century of international law, and four decades of Congressional legislation, President Obama, Secretary Kerry, and Ambassador Samantha Power are going to have to make the case to Congress and to the Security Council.

America, that is the hard work that is necessary. There is no excuse for a half-baked case and there is no excuse for claims of urgency when tens of thousands of Syrians have already died with little fanfare in Washington.

If America wants the Assad government – or any other government for that matter – to obey by the strictures of international law, the West must set the standard for responsible adherence.

Invading Syria now not only fails on that front but also further undermines the West’s ability to forge agreement around this entire premise. And what a crime that would constitute.

Democrat Raul Grijalva represents Arizona's 3rd congressional district in the U.S. House of Representatives. He is the co-chair of the Congressional Progressive Caucus.

Michael Shank is director of foreign policy at the Friends Committee on National Legislation.