President Obama’s intention to keep the United States out of “perpetual war” has been facing domestic political opposition, especially as the Islamic State has expanded its territory in Iraq and Syria. The United States and its allies have reached a preliminary agreement with Iran over that country’s nuclear program, even as Israeli Prime Minister Benjamin Netanyahu and congressional Republicans pushed Obama to take a harder line. Obama also began restoring relations with Cuba after more than 50 years of U.S. policy based on economic and diplomatic isolation of the island nation. The president’s responses to foreign policy challenges could be a factor when American voters choose his successor in 2016.

An elderly Iraqi woman hugs a soldier after government forces drove the so-called Islamic State (also known as ISIS or ISIL) out of Tikrit on March 11, 2015. On May 17, however, ISIS captured the key city of Ramadi, as Iraqi forces fled the provincial capital. Some in Congress do not feel President Obama’s approach in Iraq — providing air strikes and training Iraqi forces — will halt ISIS. (Getty Images/Anadolu Agency/Ali Mohammed)

The militant extremist Islamic State (also known as ISIS or ISIL), seeking a regionwide Islamic caliphate, has taken over swaths of land in Iraq and Syria. The group’s violent tactics, which it publicizes widely in gruesome videos, have been circulated on social media and serve to attract recruits to ISIS.

U.S. intelligence sources estimate that ISIS force levels top 20,000 — some 3,400 of them from Western countries, including more than 150 from the United States. 1