All Policy Analysis by James Jeffrey

The assertion that such an effort would require up to 30,000 U.S. troops, and that it could risk a direct confrontation with Russia, requires a much closer look.

UN Security Council Resolutions 2170, 2249, and 2254 offer ample grounds for establishing a zone to protect refugees and counter the Islamic State, but shaping the international diplomatic response would be paramount given the legal gray areas inherent in such action.

Understand the policy implications of humanitarian safe havens, safe zones, buffers, or no-fly zones in Syria with these assessments of the who, what, where, why, and how of the various options.

If Moscow can get away with boldly flouting U.S. interests in a key American security zone such as the Middle East, where might it interfere next, and at what cost to the international security system?

The potential risks of inaction -- including thousands more civilians killed, millions more refugees, the spillover of fighting into Turkey, Jordan, and Israel, and a Russian-Iranian military victory -- greatly outweigh the dangers of moving forward.

The situation in the Middle East is beginning to resemble the Balkans: either the Balkans in the early 1990s, before Washington woke up and played its role as security leader, or the Balkans before World War I, when no one woke up.

If the Obama administration sees the nuclear agreement as a strategic win capable of transforming Tehran's hostility, then America's ability to deter and contain Iranian challenges will be eroded.

Once Washington sees that defeating ISIS and dealing with the aftermath are two separate, albeit linked, operations, then the cost and benefits of using U.S. ground troops for the former can be soberly assessed.

The traditional American ally states in the Middle East do not have the strength to tackle the twin challenges of ISIS and Iran on their own, yet Washington remains more or less AWOL while its main partners fixate on domestic discord.

Moscow's lack of easy retaliatory options and Ankara's longstanding fear of Russia should forestall any showdown requiring NATO intervention, and the recent shootdown incident will help bring Ankara closer to the alliance in the long term.

Experts weigh in on key questions regarding the perpetrators of the Paris attacks and the proper response, including counterterror and military measures in Syria and Iraq.