I’ve seen the phrase "drumhead justice" a few times recently and wondered both what it means and what it implies. I found an alternate definition of drumhead meaning "carried out swiftly or summarily", but I’ve seen drumhead justice used more often seeming to imply lack of a coherent larger plan than swiftness.

Any thoughts?

Since everyone else has been silent on this I’ll give it a go.

I’ve heard the phrase "drum up charges" and the equivalent "trump up charges", both of which imply the creation of charges (usually criminal) "out of whole cloth" as it were.

I would interpret drumhead justice to characterize a lynch mob mentality or a sort of trial by headlines.

Demijohn

Hmm.  Doing a Yahoo search turned up this page at Hyper Dictionary with Thesaurus entries for give-and-take.  Not quite halfway down is drumhead justice.  Clicking on drumhead gives a page with various definitions related to drinking alcohol:  

bender, bloat, blotter, booze, boozehound, boozer, brannigan, bust, drunk, guzzler, inebriate, jag, lush, soak, sot, souse, spree, tear, tippler

Of course, there are no corresponding dictionary or thesaurus entries for the phrase.

Further checking on yDc’s home page under English Dictionaries, specifically the Century Unabriged (1899) Online Dictionary, under drumhead yielded an entry for Drumhead Court Martial with a note to see court martial under court.  Proceeding on to court and thence to court martial yielded only the definition of a court martial.  But I vaguely remember something about someone sitting on a drum . . .

The next step was the Webster’s 1828, alas, to no avail.  Next, the Webster’s 1913.  Zilcho.  Ditto for the 1911 Encyclopedia Britannica.  But, finally, a close match in the Ultralingua English Language Dictionary:

3. drumhead court-martial n. A military court convened to hear urgent charges of offences committed in action.

Further efforts were all to no avail, even the Online Etymology Dictionary.  Who has access to an Oxford ED?

From the research so far, I have a feeling it was originally a field court-martial for offences such as desertion, cowardice, mutiny, or dereliction of duty, perhaps with the presiding officer sitting on a drum(head).  In some instances it seems to be used as a synomym for a kangaroo court.

I’m not an expert on the subject, but I did find that term in Melville’s Billy Budd. When Billy strikes and kills Claggart, a drumhead court is convened to decide Billy’s fate. So, I agree with "field court-martial for offences such as desertion, cowardice, mutiny, or dereliction of duty." The "drum" part might come from a connection to the battlefield and the spontaneity of the court.