From Spencer Ackerman, Danger Room:  Marine Gen. James Mattis, the outgoing commander of U.S. troops in the Middle East and South Asia, told a Senate panel on Tuesday that he’s got “options prepared” to secure Syria’s deadly chemical arsenal.

Mattis conceded that it would be “very difficult” to prevent a chemical attack by dictator Bashar Assad’s forces. But Mattis told the Senate Armed Services Committee that after his forces detected an initial chemical attack, they might “disrupt” a poison-gas onslaught and “might be able to further affect their transfer or use. . . .”

Mattis expressed doubt that there will be a stable post-Assad Syria. Iran would view its proxy Assad’s downfall as “the biggest strategic setback for Iran in 25 years” and begin arming and training militias for a “Lebanese Hezbollah-type effect.” Mattis said the Iranian Revolutionary Guard Corps is “both on the ground [in Syria] and are bringing in foreign fighters.”

All that creates the prospect that Iran and its allies would seek to fight U.S. forces for control of Assad’s chemical arsenal — and that Mattis’ plans might have to contend with sending troops onto an active chemical battlefield.  (photo: Chris Maddaloni/Army Times)