IIRC, the authorizations for deployment are limited to 90 days unless specifically authorized by Congress. I don't know whether the authorization for continued deployment in Afghanistan had any time limitations or whether it was open ended. If it was open ended then it was effectively a declaration of war and Larkin is screwed. If it required a request for extention at any time since Obama became president then Larkin would have a valid reason to demand proof of eligibity before deployment. It all depends on whether this is still Bush's war or whether it is now Obama's war.
Deployment orders are generally open-ended. Secty Gates set policy a few years ago saying that deployments for active duty ARMY troops (LTC Lakin is active duty) should be expected to be a total of 15 months with a guaranteed 12 months at a regular stateside or overseas garrison.
The Authorization for Use of Military Force Against Terrorists (Pub.L. 107-40, 115 Stat. 224, enacted September 18, 2001)
Introduction
Begun and held at the City of Washington on Wednesday, the third day of January, two thousand and one,
Joint Resolution
To authorize the use of United a States Armed Forces against those responsible for the recent attacks launched against the United States.
Whereas, on September 11, 2001, acts of treacherous violence were committed against the United States and its citizens; and
Whereas, such acts render it both necessary and appropriate that the United States exercise its rights to self-defense and to protect United States citizens both at home and abroad; and
Whereas, in light of the threat to the national security and foreign policy of the United States posed by these grave acts of violence; and
Whereas, such acts continue to pose an unusual and extraordinary threat to the national security and foreign policy of the United States; and
Whereas, the President has authority under the Constitution to take action to deter and prevent acts of international terrorism against the United States: Now, therefore, be it
Resolved by the Senate and House of Representatives of the United States of America in Congress assembled,
[edit] Section 1 - Short Title
This joint resolution may be cited as the ‘Authorization for Use of Military Force’.
[edit] Section 2 - Authorization For Use of United States Armed Forces
(a) IN GENERAL- That the President is authorized to use all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons.
(b) War Powers Resolution Requirements-
(1) SPECIFIC STATUTORY AUTHORIZATION- Consistent with section 8(a)(1) of the War Powers Resolution, the Congress declares that this section is intended to constitute specific statutory authorization within the meaning of section 5(b) of the War Powers Resolution.
(2) APPLICABILITY OF OTHER REQUIREMENTS- Nothing in this resolution supercedes [sic] any requirement of the War Powers Resolution.