Read Starlac's review below, because I pretty much agree with everything he said. I just differ slightly in how strongly I believe the same things.
Donald's inducement to join the army is an opening scene where he is surrounded by billboards of voluptuous women falling all over military men - maybe a little more risque than usual for Disney (if I remember correctly he does actually see an air force and maybe a navy one, too, but still chooses the army.) This is effectively the same motivation that made Popeye and Bluto try to sign up in 'I'm in the Army now' (1936) - i.e. Olive loves a man in uniform. And in fact, Popeye was in a sailor suit as well, and also chose the army - which wasn't even nescessary plot-wise, since the short was completely about him trying to be recruited, not anything that happened afterwards.
Anyway, Donald is put through a rigorous and quite silly screening process, and then assigned to the imposing Sergeant Pete, with whom he immediately gets on very badly.
I'm a bit less tough on Donald here. His temper isn't really absent, just subdued. He does get quite cranky at various stages, but, unusually, he tries to keep it to himself, which actually adds a little frustrated tension. But I do have some confusion as to what sort of message this cartoon was trying to send to potential recruits (which, while I think of it, leads me to ask, why is it called 'Donald gets Drafted'? He enlisted, didn't he? Or did 'draft' have a different meaning in the US back then?)
In any case, consider the following. The Army evidently accepts people who are
a) mentally deficient
b) incompetant
and when they join, they
c) treat them really badly and make them do menial, demeaning things.
I wonder how many recruits this short actually created?
The other problem is, was Donald the right sort of character to get drafted in the first place? As Starlac observed, his temper either had to be kept in check, at the expense of losing laughs, or allowed full reign, at the cost of probably making the army look unable to control its recruits.
Mickey Mouse would have been an even worse choice. He would have obligingly done whatever was asked of him, and probably would have passed the medical, too.
I think Goofy would have been the best choice. He would automatically have gotten everything wrong, driven everyone mad, and there could have been the added humour of him half the time not even realising he was doing it. Yes, I think Goofy gets Drafted is a much more comically appealing idea. But Goofy wasn't Disney's biggest star, and it's pretty obvious why Donald got this gig.
Falls over the line into 2.5 for me, just. Quite watchable but nothing to write home about.
Incidentally, I have a beef with Disney's 'Chronological Donald'. To watch any of the war-themed Donald shorts, you have to sit through 2 minutes of Leonard Maltin being politically correct - which wouldn't be so bad, except that you can't damn well fast forward through it. Now nothing against Maltin, but that 2 minutes gets very long when you have to watch it every time you want to watch a 7 minute short (fortunately once you get through it you can select a cartoon from that sub-menu without having to listen to him all over again. I don't know if the 'On the Front Lines' version has the same sort of problem.)