White Christmas

We'll follow the old man wherever he wants to go

As long as he wants to go opposite to the foe.

We'll follow the old man wherever he wants to stay

As long as he stays away from the battle fray.

Because we love him, we love him,

Especially when he keeps us on the ball.

And we'll tell the kiddies we answered duty's call

With the grandest son of a soldier of them all!

Take Bing Crosby and Danny Kaye, mix in a bunch of Irving Berlin tunes, and throw in a light but solid plot to put them all together. That's more or less what this film is.

The plot is worth noting, though. The two leads play Bob Wallace and Phil Davis, a mid-level entertainer and a nobody who meet up as they fight in World War II in the same unit. In the wake of an at-the-front Christmas show thrown as a farewell to their respected leader, General Waverly, Phil saves Bob's life, taking an injury of unspecified degree in the process.

Phil -- himself a wannabe entertainer -- uses both Bob's gratitude and his guilt over the injury to convince him to try a partnership after the war. Despite Bob's initial misgivings, the pair not only work, they become one of the biggest acts in the country, moving in ten years from club gigs to their own radio show and ultimately to writing and producing their own Broadway revue.

On Christmas Eve on tour in Florida with the show, they receive a letter from Benny Haynes, another soldier from their old army unit, asking them to look at his sisters' nightclub act. It later turns out one of the sisters faked the letter, and the other sister is shocked at the dishonesty. It works, though, and Wallace and Davis actually end up falling for the sisters (but not willing to admit it yet), and even follow them to their new gig in Vermont. There they see it's got a warm spell, and even though it's the beginning of winter it's 70 degrees and there's no snow in sight. The owner of the lodge hires them anyway, and he turns out to be the now-retired General Waverly.

Okay, that seems contrived, but that's not the point. Aside from the musical numbers, the film keeps a strong focus on both the growing relationships between the male and female leads, and just as strong a focus on how Waverly feels washed up after leaving the army, and how Wallace and Davis manage to lift his spirts.

The film may seem odd to some, especially how Danny Kaye's socially awkward character seems Ambiguously Gay to some these days (he's more meant to be a big kid, as indicated by his voice cracking at awkward moments).

For the trope about snow at Christmastime, see Dreaming of a White Christmas.

Tropes used in White Christmas include:

Acid Reflux Nightmare: Bob informs us that if you eat liverwurst sandwiches right before bed you will "dream of liverwurst." That doesn't sound very pleasant.
Arc Words: "Let's just say we're doing it for an old pal in the Army."
Birds of a Feather: Phil and Judy, Bob and Betty.
Body Language: Watch Bob and Bety's argument at Novello's, after Phil and Judy head off to dance. Despite the coldly angry words, with each exchange they readjust their seats and postures to get closer and closer to each other.
Bowdlerization: Small in-universe example: the General has Bob skip a dirty word in a letter he's reading aloud.
Captain Ersatz: Ed Harrison, who hosts one of the most popular variety shows in the country.
Costume Porn: Very low-key at times, and all but over-the-top at others. This is a film costumed by Edith Head, after all.
Dawson Casting: 32-year-old Vera-Ellen as "Little Judy", who appears from all evidence to be about 19. (By contrast, older sister Betty was played by 25-year-old Rosemary Clooney.)
Deadpan Snarker: Emma gets in some good zingers:

Waverly: I got along just fine in the Army without you.

Emma: It took fifteen thousand men to take my place!

Department of Redundancy Department: "If you're worried and you can't sleep/Just count your blessings instead of sheep/And you'll fall asleep counting your blessings."
The Ditz: Doris Lenz, the "Mutual, I'm sure" girl.
Dramatically Missing the Point: Bob thinks Betty is just being difficult, and not seeing that something is actually upsetting her.
Dreaming of a White Christmas: Subverted, until the end.
- In case you're wondering, it isn't the Trope Namer -- that was Holiday Inn.
Exact Eavesdropping: Subverted; Emma Allen is distracted at exactly the wrong moment while listening in on a phone call, making her think Bob wants to make a fool out of the General. And then she tells Betty...
A Father to His Men: Waverly.
Funny Background Event: Watch the reunited soldiers during the tribute to General Waverly at the end -- there're lots of little bits of funny business. For instance, when he says "Ties will be worn in this area!", one fellow grins broadly and makes a point of very obviously adjusting his (already perfect) tie.
Glory Days: Waverly tries to return to active service in the army, but they have no place for him.
"Happy Holidays" Dress: Two stunning ones worn by the Haynes sisters at the end.
Have a Gay Old Time: When Judy enumerates her requirements for a suitable candidate to be her bogus fiance, she includes "handsome ... gay ... witty".
Headbutting Heroes: Bob and Betty, but only for the first five minutes together, and later when they get crossed wires (see Exact Eavesdropping).
Heterosexual Life Partners: Wallace and Davis.
Hey, Let's Put on a Show: Large elaborate dance scenes took up a lot of the movie time.
History Marches On: Crosby at one point mentions that it would be "impossible to find a Democrat in Vermont". Back in the day, Vermont was a GOP stronghold. Not so much now...
Hollywood New England
I Owe You My Life: Subverted; throughout the film we see Phil constantly reminding Bob of his "war wound", so he'll do what Phil wants -- i.e. form the double act, become producers, go to Vermont, etc. Granted, we wouldn't have a plot otherwise, but on the other hand you can sympathise with Bob when he vents about how manipulative Phil is being.
May-December Romance: Both Bob-Betty and Phil-Judy. Bob is clearly in his forties in 1954, and while Phil could conceivably be as young as his late twenties it's far more likely he's in his middle thirties. Meanwhile Betty is no more than 25, and Judy is probably 19.
Montage: Several, including a Time Compression Montage showing the progress of Wallace and Davis's joint career.
Musical
Pair the Spares: Judy and Phil deliberately invoke this in order to get Betty and Bob back together. It doesn't go quite as planned. But they all end up as couples anyway.
Pretty in Mink: The dresses at the end are trimmed with white fox and come with matching muffs.
- The fur wraps worn by all the wives and girlfriends of the soldiers showing up at the end.
Scenery Censor: Bob's trunk in the dressing room during his argument with Phil early in the film. If you're not paying attention, you won't notice that Bing Crosby strips to his underwear and changes his clothes entirely, all on camera, thanks to that trunk.
Self Plagiarism: Not at all uncommon in an Irving Berlin film (as his contracts mandated no music but his own in them), but taken to new heights here. Besides the wholesale recycling of numbers originally seen in Holiday Inn as parts of Wallace and Davis' stage show, there are quotes or entire songs from a handful of other Berlin films. Additionally, the verse melody from Holiday Inn's "Happy Holidays" is repurposed as the bridge of "Counting Your Blessings".
Shaped Like Itself:

Betty: We'll be in Vermont.
Bob: Hmm. Sounds very... Vermonty.

Showgirl Skirt: Judy wears a detachable one in the "Mandy" number.
Soundtrack Dissonance: Singing "I'm Dreaming of a White Christmas" in the middle of a destroyed town during WWII to a group of sad soldiers. Singing the same song while it's snowing? Um...
- Except that at that point they are dreaming about it; despite the fact that it's Christmastime at a ski resort in Vermont, the weather is clear, sunny and warm -- and they need the snow to save the General's business.
Spinning Newspaper: A variation is seen the post-war Time Compression Montage, when multiple Variety headlines are displayed, tracking Wallace & Davis's career.
Spiritual Successor: To Holiday Inn. It was originally intended as a vehicle to reunite Crosby and Fred Astaire, but Astaire considered himself retired at the time and the part eventually went to Danny Kaye and the script was dramatically re-written.
Take That: Choreography is one big Take That against Martha Graham and the Modern Dance movement.
The Men First: General Waverly, as Bob fondly remembers.
They Wasted a Perfectly Good Sandwich: Averted by Betty during the first dinner at the Inn -- because Rosemary Clooney was too inexperienced an actress at the time to realize that she shouldn't really eat the food, especially through multiple retakes and alternate angle shots.
Throw It In: Bob's speech about the effects of sandwiches on dreams was completely improvised by Crosby.
- Much of Bob's odd lingo and slang was Bing Crosby's usual way of speaking applied to the script.
- The reprise of "Sisters" lip-synced by Bob and Phil allegedly began as a gag pulled by Bing Crosby and Danny Kaye during filming. The director liked it so much the script was re-written to include it.
Titled After the Song
Undisclosed Funds: Because "Wow!" doesn't need to adjust for inflation, and it's funnier than an actual number.

Phil: H...How much is "wow"?

Bob: Somewhere between "ouch!" and "boinnnnnng!"

Phil: Wow!

Values Dissonance: What a difference sixty years makes -- Bob basically wants a wife who will stay in the kitchen and bear his children, and despite being career girls, neither Betty nor Judy have a problem with that, nor does Betty object to the implication that she'll have to give up show business to marry Bob.
Wakeup Makeup: Betty and Judy seem to go to bed with their hair still styled and wearing full make up. That red lip stick isn't going to do any favors to your pillow, Betty.
Weather Dissonance: The plot hinges on the fact that there's no snow. Vermont would normally be draped in snow by Christmas, but it's basically spring weather there. No snow means no business, and no business is bad for Waverly.
World War II: The movie opens there, and three of the main characters served.