United States Department of State

Whaliington, D. C. 20520

 

The Honorable

Bob Corker, Chairman
Committee on Foreign Relations
United States Senate
Washington, DC 20510

AUG 2 2017

Dear Mr. Chairman:

Thank you for your letter of June 21, 2017, regarding the legal basis for the use of force in US.
military actions in Syria in May and June 2017. 

The United States has suf?cient legal authority to prosecute the campaign against al-Qa?ida and
associated forces, including against the Islamic State of Iraq and Syria (ISIS). This legal
authority includes the 2001 Authorization for the Use Military Force (AUMF) which authorizes
the use of military force against these groups. Accordingly, the Administration is not seeking
revisions to the 2001 AUMF or additional authorizations to use force.

The 2001 AUMF also provides authority to use force to defend U.S., Coalition, and partner
forces engaged in the campaign to defeat ISIS to the extent such use of force is a necessary and
appropriate measure in support of counter-ISIS operations. As Secretary Tillerson indicated in
his testimony before the Committee on June 13, 2017, our purpose and reason for being in Syria
are unchanged: defeating ISIS. The strikes taken by the United States in May and June 2017
against the Syrian Government and pro?Syrian-Government forces were limited and lawful
measures to counter immediate threats to US or partner forces engaged in that campaign. The
United States does not seek to ?ght the Syrian Government or pro-Syrian?Government forces.
However, the United States will not hesitate to use necessary and proportionate force to defend
U.S., Coalition, or partner forces engaged in the campaign against ISIS.

As a matter of international law, the United States is using force in Syria against al-Qa?ida and
associated forces, including ISIS, and is providing support to Syrian partners ?ghting ISIS, such
as the Syrian Democratic Forces, in the collective self-defense of Iraq (and other States) and in
US. national self-defense. Upon commencing airstrikes against ISIS in Syria in September
2014, the United States submitted a letter to the UN. Security Council consistent with Article 51
of the UN. Charter explaining the international legal basis for its use of force. As the letter
explained, Iraq has made clear that it faces serious threats of continuing armed attacks from ISIS,
operating from safe havens in Syria; the Syrian Government has shown it cannot, or will not,
confront these safe havens. The Government of Iraq has requested the United States lead
international efforts to strike ISIS sites and strongholds inside Syria to end armed attacks on Iraq,

to protect Iraqi citizens, and to enable Iraq to control its borders. Moreover, ISIS threatens Iraq,
U.S. partners in the region, and the United States. Therefore, consistent with the inherent right
of individual and collective self-defense, the United States initiated necessary and proportionate
actions in Syria against ISIS in 2014, and those actions continue to the present day. Such
necessary and proportionate measures include the use of force to defend U.S., Coalition, and
U.S.-supported partner forces from threats by Syrian Government and pro-Syrian Government
forces.

We hope this information is useful. Please do not hesitate to contact us if we can be of further
assistance.

Sincerely,

Charles Faulkner
Bureau of Legislative Affairs