I practice appellate criminal defense in a Federal Public Defender office. I have a bit of experience in military law, but it was scant, and years ago. Still, the following information and observations are a place to start.
The modern Uniform Code of Military Justice ("UCMJ") became effective 31 May 1951. Previously, military justice had been governed by the Articles of War. In the Mad Men timeline, Dick Whitman's offenses took place, or commenced, before the effective date of the UCMJ. I have no idea whether a military prosecution of Whitman in 1963 would proceed under the UCMJ, or the Articles.
The UCMJ is found in Title 10, Subtitle A, Part II, Chapter 47 of the United States Code. One may access it at:
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The text is also available at:
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Setting aside the Articles v. UCMJ question, Whitman should be subject to military justice, notwithstanding his nominal civilian status, pursuant to 10 U.S.C. § 802(c), which provides that "a person serving with an armed force . . . is subject to [the UCMJ] until such person’s active service has been terminated in accordance with law or regulations . . . ." It certainly appears that Whitman's service was never lawfully terminated; it was fraudulently terminated. Therefore, he is presumably still subject to the UCMJ.
The UCMJ statute of limitations is at 10 U.S.C. § 843. Subsection (a) provides that:
"A person charged with absence without leave or missing movement in time of war, . . . or with any other offense punishable by death, may be tried and punished at any time without limitation."
On the face of this provision, Dick Whitman, while presumed dead, is actually absent without leave, and thus is still subject to prosecution in a court martial.
I believe he might also be subject to a charge of desertion. Pursuant to 10 U.S.C. § 885,
"(a) Any member of the armed forces who—
(1) without authority goes or remains absent from his unit, organization, or place of duty with intent to remain away therefrom permanently;
(2) quits his unit, organization, or place of duty with intent to avoid hazardous duty or to shirk important service; . . .
is guilty of desertion.
. . . .
(c) Any person found guilty of desertion or attempt to desert shall be punished, if the offense is committed in time of war, by death or such other punishment as a court-martial may direct . . . ."
Because the charge, desertion in time of war, would be punishable by death (even if that is not actually the punishment imposed), then no period of limitation would apply, and Whitman presumably could still be subject to military prosecution in 1963.
Apart from those offenses, subsection (b)(1) of § 843 provides that:
"Except as otherwise provided in this section (article), a person charged with an offense is not liable to be tried by court-martial if the offense was committed more than five years before the receipt of sworn charges and specifications . . . ."
(Emphasis added.) That would seem to spare Whitman from the threat of prosecution for offenses committed in 1950 or 1951, as long as those offenses are not the ones specified in subsection (a) (i.e., absence without leave, or a capital offense). But he might still be at risk if the offense is considered a continuing offense. Another possible risk of prosecution -- one that's by no means clear from the information the show has given us -- might arise if he is receiving any veteran's benefits as Don Draper that he would not be entitled to as Dick Whitman. That type of fraudulent act would likely be prosecutable either in the military justice system, or by civilian federal prosecutors.
Keeping in mind that these may be outside the period of limitation, here are some offenses Whitman may have committed:
10 U.S.C. § 883 provides that:
"Any person who—
(1) . . .
(2) procures his own separation from the armed forces by knowingly false representation or deliberate concealment as to his eligibility for that separation;
shall be punished as a court-martial may direct."
Under 10 U.S.C. § 892, someone who:
"(1) violates or fails to obey any lawful general order or regulation;
(2) . . . ; or
(3) is derelict in the performance of his duties,"
is subject to military prosecution.
10 U.S.C. § 907 provides for the punishment of a person who makes false official statements -- such as, say, Dick Whitman signing discharge documents as Don Draper.
10 U.S.C. § 932 provides for the punishment of frauds against the United States. This is one that at least plausibly might be construed as a continuing offense; it would depend on facts of the case, such as whether Dick is receiving veteran's benefits as Don.
I have not found any UCMJ provision that identifies the fraudulent assumption of another soldier's identity, or the impersonation of an officer, as a specific offense. It could be that those acts are chargeable only as violations of more general provisions, such as those I have cited above.