The U.S. could be headed into a war with Iran without any debate in Congress, according to lawmakers who have spoken out about their concerns in recent weeks.

“If you are going to put 1,000 troops inside Syria… the ultimate result of that will be to put US forces in direct confrontation with either Iranian forces or Iranian proxy forces,” said Senator Chris Murphy (D-CT) at the Center for New American Security’s annual conference last week. “There is currently military activity happening inside Syria that is not authorized,” Murphy cautioned, saying that a Congressional debate on whether to provide such authorization is long overdue as the escalating conflict could lead to a long term confrontation between U.S. forces and Iran.

After a U.S. Air Force fighter shot down an Iranian-made drone in Syria, lawmakers did discuss the legality of American intervention in Syria at a Senate Foreign Relations Committee hearing in June. John Bellinger, former counsel for the Bush Administration, testified about his concerns that a 2001 authorization for military force passed by Congress after the September 11th attacks was not sufficient justification for U.S. actions in Syria. “On Syria, I have to say, just on the law, I was puzzled about the statements coming out of the Pentagon that the shoot-down was authorized by the 2001 AUMF,” Bellinger said.

The attack was a part of the United States’ greater strategy of deploying a small group of forces to al-Tanf to train up Sunni forces, which would then take on ISIS before turning their attention to Assad. However, Assad-aligned and Iranian-backed forces do not appear eager to cede a significant portion of the country to U.S.-backed rebels. In the midst of the U.S. downing of a Syrian jet and reports of Iranian drones and Iranian-backed forces operating nearby, many hawks inside the beltway have urged the administration to more aggressively rollback Iranian forces embedded in Syria.

As the U.S. military presence in Syria has ramped up in preparation for an assault on ISIS strongholds in the country, the U.S. has increasingly struck Assad-aligned and Iranian-backed forces operating in the country. These military confrontations have increased the risk of the U.S. being dragged into conflict with the Syrian regime, Iran and Russia – a prospect that would almost certainly further destabilize the region. The White House has also warned against future chemical attacks on the Syrian people by the Assad regime. Last week, U.S. Ambassador to the United Nations Nikki Haley made an official statement on Twitter, warning that, “Any further attacks done to the people of Syria will be blamed on Assad, but also on Russia & Iran who support him killing his own people.” The warning increases the risk that the U.S. would consider a military response against Russian and Iranian forces, even without a Congressional authorization.

Despite the recent engagements with Syrian and Iranian-backed forces, even members of the Trump Administration have disagreed as to whether such actions are on sound legal footing. During the Review of the Fiscal Year 2018 Budget Request on June 13th, Senator Murphy asked Secretary of State Rex Tillerson, “would you agree that there is no legal authorization granted to the Administration by Congress to wage war against the Assad regime or against the Iranian proxies?” Tillerson confirmed that he would agree with that statement, which would appear to rule out military action against Assad-aligned forces in Syria.

Yet, later at a National Press Club luncheon, Chairman of the Joint Chiefs of Staff General Joseph Dunford appeared to contradict Tillerson’s assessment. When Jeff Ballou, President of the National Press Club, asked Dunford to explain the legal justification for targeting Syrian government forces, he replied “[w]e are there and have legal justification under the Authorization for Use of Military Force. We’re prosecuting a campaign against ISIS and Al Qaeda in Syria.”

Dunford did not directly answer the question, but implied that an existing authorization of force against terrorist organizations involved in 9/11 gives him the legal authority to target the Syrian regime. There was much debate and disapproval when Obama used the 2001 authorization to justify air attacks against ISIS in Libya.

The S.J. Res. 23 Authorization for Use of Military Force (AUMF 2001) was created by the Bush Administration following the 9/11 attacks. The resolution gave the United States Armed Forces the power to use “all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons.”

Subsequently, Congress passed the 2002 Authorization for Use of Military Force Against Iraq (AUMF 2002), which authorized the President to “use the Armed Forces of the United States as he determines to be necessary and appropriate in order to defend the national security of the United States against the continuing threat posed by Iraq.” While this resolution specifically focuses on Iraq, the phrase “by Iraq” arguably broadens the scope to threats that arise as a byproduct of actions in Iraq.

The Obama administration was open to amending these authorizations, yet used them to justify its campaign against ISIS by reasoning that ISIS was an outgrowth of al-Qaeda in Iraq. In 2016, The Obama White House released a report on the legal and policy frameworks guiding the use of the authorizations. In this report it states that “the 2001 AUMF and, in certain circumstances, the 2002 AUMF authorize the use of force in Syria against al-Qa’ida in Syria and ISIL.” Nowhere in this report does it mention extending this authorization to include attacks against Assad’s forces or any other forces operating in Syria.

The lack of a unified stance on the 2001 AUMF’s reach, particularly in the case of Syria, shows the murky legality of U.S. involvement in the conflict. With such high stakes, a formal debate in Congress addressing the issue of military force may be necessary to provide clarity regarding the U.S. military’s role in Syria and prevent a slide into war.