Title says it all. What is the relevance of the theme song to the movie, if any?
The dentist, played by John Shuck (and not in the TV series), was nicknamed “Painless”. He attempted suicide - remember the “black pill” and the pre-suicide wake Hawkeye and Trapper staged for him so he could enjoy it? Painless’ waking up anyway, next to a hot nurse? Perhaps Loudon Waiinwright was simply inspired by the scene. The song does have a fatalistic, every day could be your last so make the best of it kind of flair to it that sort of fits the atmosphere.
IIRC, the song was written by Robert Altman’s teenage son.
Thanks. Probably time I watch the film again. It’s been so long, I can’t even really remember the movie. Perhaps I’ll rent it this weekend!
Loudon Wainwright was briefly in the TV series (he did the “Oh, Tokyo” song), which is undoubtedly where the confusion came from.
His character’s name was, if I recall correctly, Captain Spalding.
Because it brings on many changes, and you can do the same thing if you please.
Does anyone remember the book? The dentist was known as the “Peerless Pole” who was the proud owner of “The Pride of Hamtrack”.
And he wanted to kill himself because he was suffering a bout of impotence.
I’m pretty sure he was also the “Painless Pole” in the book.
Walter Waldowski, the Painless Pole, owner and operator of the “Pride of Hamtramk” (fairly sure that’s the right spelling). Read the book, oh, say, 28 years ago, plus a number of the sequels 
Took a black capsule on the advice of the doctors and when he woke up (after a big “going away” party and the last rites from Father “Dago Red” Mulcahy), the Pride had a blue ribbon tied around it - from which Painless concluded that, wherever he’d just been, he’d won first prize.
And, IIRC (but it’s been years), he was worried that meant he might be gay.
As well, again IIRC, the others would stand in line at a peephole in the shower hut to catch a glimpse of his equipment.
I believe you are correct about The Peerless Pole being concerned that he might be gay. I also seem to recall that part of the “treatment” included a visit from one of the nurses while still in a semi-stupor after taking the black capsule, after which the blue ribbon was attached to the Pride.
Also IIRC one visiting soldier after viewing the Pride in the shower commented “Ah’d surely like to see that angry.”
Hawkeye, I believe, convinces the nurse to perform this one good deed–saving a man’s life–before she leaves Korea. I like the close-up on her beatific face as she flies away in a helicopter the next day as Painless goes enthusiastically back to work.