In January, in a public address at a Washington think tank, then-Secretary of State Rex Tillerson attempted to explain the significant shift in the Trump administration's Syria policy now that the Islamic State terrorist group was been pushed into smaller and smaller pockets of terrain.

Keeping ISIS contained so it doesn't regenerate, Tillerson said, was only a fifth of the battle. Washington will also drastically expand into far-reaching objectives: assisting with post-conflict reconstruction; keeping U.S. troops in Syria until Bashar al-Assad is removed from power; combatting Iranian influence; and creating the conditions for millions of Syrian refugees to finally return to their homes.

If you were wondering what legal authority the administration is using to underpin this increasingly broad mission, you are not alone. The Trump administration has been suspiciously quiet about the legal question, perhaps recognizing how flimsy their legal arguments are. When administration officials are pressed for details, they cite the 2001 and 2002 Authorizations for Use of Military Force (AUMF) as catchall legal authority and an expansive view of the president's authority to commit troops into a conflict.

The Trump White House, of course, is not the only administration to use the 2001 AUMF is this way. An authorization that was designed to retaliate against the group that perpetrated the 9/11 attack (al-Qaeda) and the quasi-government that harbored them (the Taliban) long ago turned into a legal elastic band. Terrorist organizations around the world that have only minimal or symbolic connections with Osama bin Laden's original group of jihadists are categorized as Al-Qaeda affiliates and therefore targetable under the 2001 resolution. Never mind that the word "affiliate" does not appear once in the text of that 60-word resolution—or that some of those affiliates are not really affiliates at all, but rather local extremists with hyper-local concerns hoping to exploit the al-Qaeda or ISIS brand to attract cash and recruits.

The Trump administration, however, is unique in one important respect: It is the first to use a resolution passed over 16 years ago as legal justification against targets—the Assad regime and Iran—that had nothing whatsoever to do with the al-Qaeda or the 9/11 attacks.

The White House is cloaking a policy of regime change in Syria under the guise of fighting terrorism and preventing the Islamic State from returning—a policy that the American people neither want or were consulted on. The United States is dangerously setting new missions that have absolutely no connection at all to combatting ISIS.

There was once a time when the president and his national security team would need to make the case to lawmakers and the American people before deploying U.S. ground troops on an open-ended mission. The American people would be given the opportunity to weigh in and members of Congress would be provided the chance to ask questions and debate amongst themselves on whether removing another govenrment in the Middle East would be any more wise than previous regime change disasters in Iraq and Libya. Millions of politically active Americans, having seen with their own eyes over the last decade and a half how little gain the United States receives from toppling governments in countries we barely understand, would flood Capitol Hill with phone calls and register their concerns and warnings. Unfortunately, that is not how the process works anymore—the executive branch need not concern themselves with such annoyances.

Why go back to Congress for additional statutory approval and follow the Constitution when you can follow the path of least resistance?

The executive branch is only part of the problem. An even greater share of the blame lies on the shoulders of Congress, an institution that has deferred ever more war-making power to the president in order to avoid the most solemn constitutional responsibility—taking a difficult war vote. While there are exceptions to the rule, the institution has been content with taking the White House's case for granted. Until the congressional leadership is forced to hold the executive branch accountable on matters of war and peace, the status-quo will continue, and the balance will only get more lopsided.

A debate over military action, particularly one centered on a fourth regime change operation in the Middle East in 15 years, should not be a discussion confined to law schools and think-tank conference rooms.

The architects of the Constitution and the founders of America's system of government were highly cognizant of the dangers of an imperial presidency, where a single man alone could determine when and where the nation goes to war. To prevent the president from exercising the powers of a monarch or a dictator, the Constitution placed the decision to declare war in the hands of the legislative branch. Transitioning the country from peace to war was so consequential and so vital to our republic that the American people, through their elected representatives, were judged to be the ultimate decision-makers on the issue.

Regrettably, we have arrived in a place where the executive branch is the sovereign and Congress is merely a peanut gallery only interested in these important matters when there is political gain to be made.

But what Congress gives, Congress can take away. And if there was ever a time for the legislative branch to reclaim its authority and stop the decades of an ever more powerful executive, it is now. If members won't reenter the game and fulfil their constitutional obligations when 2,000 U.S. troops are conducting an open-ended deployment in northeastern Syria with an impossible set of missions, then the American people can only conclude this Congress will never do its job.