From an contact of mine in DoD:

Colleagues:

The phrase "contingency operation" is a term of art in Title 10, United States Code, which is tied to the deployment of U.S. forces at home and abroad:

As outlined in the DoD definition (http://www.dtic.mil/doctrine/jel/dod...c/01233.html):

"Definition: (DOD) A military operation that is either designated by the Secretary of Defense as a contingency operation or becomes a contingency operation as a matter of law (10 USC 101(a)(13)). It is a military operation that a. is designated by the Secretary of Defense as an operation in which members of the Armed Forces are or may become involved in military actions, operations, or hostilities against an enemy of the United States or against an opposing force; or b. is created by definition of law. Under 10 USC 101 (a)(13)(B), a contingency operation exists if a military operation results in the (1) callup to (or retention on) active duty of members of the uniformed Services under certain Enumerated Statutes (10 USC Sections 688, 12301(a), 12302, 12304, 12305, 12406, or 331-335) (2) the callup to (or retention on) active duty of members of the uniformed Services under other (non-enumerated) statutes during war or national emergency declared by the President or Congress."


To this definition, I would add that "contingency operation" has specific meaning and force of law in the legal area -- with respect to 1) the triggering of UCMJ jurisdiction, and 2) the triggering of certain federal acquisition authorities, among other things.

I would speculate that the choice of this phrase was deliberate -- to bring the policy and budgetary nomenclature in line with each other. Further attempts at exegesis, and other tea-leaf reading efforts to divine meaning from this, may not produce any more substantive explanation.