US Rep. Ted Lieu, a Democrat from California, is a member of the House Foreign Affairs and House Judiciary Committees. Lieu, who is an assistant whip for the Democratic Caucus, served on active duty in the air force and is a colonel in the Air Force Reserves. The opinions expressed in this commentary are his.

(CNN) The President's strategy toward Syria has two critical defects. First, there is no strategy. Second, President Trump has never sought congressional authorization for use of force in Syria -- something that many have argued made his previous missile attack against Bashar al-Assad unconstitutional and makes any future unauthorized plans precarious at best. This is no way to deal with a complicated and deadly conflict that could spin out of control, especially if the United States intentionally or inadvertently engages Russia's military.

It is important to first acknowledge that the use of chemical weapons is horrific. Assad's suspected chemical weapons attack shows he is willing to go to barbaric lengths to hold onto power. The World Health Organization estimates that as many as 500 people -- including children -- were potentially exposed to toxic chemicals that can cause respiratory failure and nervous system damage. These reports underscore yet another heinous act in the long, calamitous conflict in Syria. In the seven-year war, more than 400,000 people have died and millions have been displaced. With Russia and Iran providing support for Assad, the challenges remain complex and unwieldy.

President Trump responded to the chemical weapons attack with characteristic tough-guy tweets, announcing plans to fire missiles at Syria and calling Assad "a Gas Killing Animal." But the President's threats of force are unlikely to accomplish much for one simple reason: There is no clear strategy guiding them. After over a year in office and 59 Tomahawk cruise missiles fired at the Assad regime, President Trump has neither articulated a plan for Syria nor seriously engaged with Congress on this issue.

A mercurial plan of action may have worked in the Trump Organization board room, but it's a disastrous tactic in foreign affairs. Just last week, the President called for pulling out of Syria. On Wednesday, he threatened launching missiles at Syria. Next week, who knows? The US cannot implement a cogent strategy on the world stage if no one is sure whether to take the President seriously. As a member of the US Congress on the Foreign Affairs Committee, I feel in the dark -- I can only imagine how the American public and our allies feel.

In fact, frustration with the President's lack of a strategy on Syria led to bipartisan agreement -- an uncommon coalescence -- that the President provide Congress with a comprehensive strategy on Syria. The Trump administration's plan, under the law, was due on February 1 . The report is now over two months late with no explanation from the White House as to why. A comprehensive Syria strategy, ideally one that's more than 280 characters, remains a key requirement to protect US interests in the Middle East.

"Bomb now, ask questions later" is not a winning strategy. It's also unconstitutional. Without an Authorization for Use of Military Force by Congress, President Trump does not have the authority to launch missiles, conduct airstrikes or use ground forces against Assad's regime.

Even though there is broad, bipartisan agreement that those responsible for these crimes against humanity should be held responsible, President Trump appears uninterested in fulfilling his obligation to Congress and the American people. Indeed, an unwillingness to work with Congress is about the only strategy we've seen from this administration.

We know that Russia, Iran and the Assad regime are willing to go to great lengths to protect their interests. Russia has stated they will defend Assad. The President in response threatened Russia, tweeting "Russia vows to shoot down any and all missiles fired at Syria. Get ready, Russia, because they will be coming, nice and new and 'smart!'" Any US strike on Syria risks engaging the Russian military. And unlike Syria, Russia is one of a few countries that could annihilate the United States with nuclear weapons.

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I served on active duty. I understand that the use of force is sometimes necessary. However, it is only effective when used as part of a comprehensive plan to achieve a specific end-state. The brave men and women in our military deserve to know that any use of force is ordered as a part of a broader strategy and that it comports with the Constitution.

President Trump needs to demonstrate that he takes his responsibilities seriously. To do so, he must present Congress with a legitimate strategy on Syria and seek congressional approval before any military strikes. Until then, a lack of strategy in Syria will continue to be a matter of life or death.