According to Colin Meloy, "Pop music has always adopted the style of marrying upbeat melodies to dour lyrics. But I think there's less irony [on The Crane Wife] than the previous records; it's more earnest. The music is there to really push up the sentiment of the songs and underscore the drama." (Source)
Even though "O Valencia" is on The Crane Wife, it does seem to follow the pop tradition of putting happy music to a sad story. Still, the music manages to "underscore the drama" in key places, including the very beginning.
The song starts with only lead guitar and drums. There are just two lonely instruments blending together, which perhaps isn't unlike how the speaker and Valencia are two lonely people who will soon find each other.
As the verse goes on, more musical layers are added each time a new obstacle to the relationship is mentioned. The first lines are, "You belong to the gang / And you say you can't break away," which outlines the first problem. The rhythm guitar and bass come at, "And our families can't agree," which is problem two.
After the second verse, we get to, "So await for the stone on your window." There's almost a hushed pause at the word "await." Even though all the instruments are heard, they sound like they're holding back until the next part of the line, "on your window, your window." This is probably the kind of thing Meloy was talking about when he said that the music is there to "push up the sentiment."
The next verses and pre-chorus are very similar to the beginning of the song. As we come to the chorus, where the title of the song is finally sung, the xylophone-sounding glockenspiel, a deep piano, and harmony vocals are all added to the mix. Along with the these additions, we learn of Valencia's death for the first time when Meloy sings, "With your blood still warm on the ground." This is pretty good evidence for the earlier idea that more instruments means more problems.
As we approach the climax of the song, where the brother "call[s] out" the speaker and Valencia is shot while trying to protect him, the music changes to a configuration we haven't heard. The lead guitar drops out, and we're only left with percussion and sparse piano notes before the "shot...hit[s] hard." Once again, The Decemberists are building up that tension. The change in the music tells us that something big is about to happen in the story, and, just as Valencia is shot, almost all the instruments we've heard so far return.
How is "O Valencia!" like the Decemberists? Let us count the ways:
(1) It uses a centuries-old story structure.
(2) It tells a tale of two ill-fated lovers.
(3) It's darn catchy.
(4) It sounds like modern indie pop, but, with Meloy's distinctive voice and lyrics, it won't be mistaken for the work of any other band.
(5) As Chris Funk admitted, "Every one of our records has an R.E.M. moment. Like on The Crane Wife, we had 'O Valencia,' and that guitar line that I put on there is 'Seven Chinese Brothers.'" (Source)
With all the air-glockenspiel that goes on when you're rocking out to "O Valencia!" you probably aren't paying much attention to the verb tenses of the lyrics. But when you take a closer look at the words, you'll notice that they make a lot of jumps in time.
The tenses in this song are all over the place, but, because we're dealing with a lyricist who has a creative writing degree and is well known for his intellectual lyrics, maybe there's a reason for it. Let's take a closer look at how the past, present, and future tenses fit into the narrative of this song.
The speaker uses past tense verbs like "gave," "swore," "heard," " ran," "hit," "went," and "was," to describe the actions that immediately surround Valencia's death.
There does seem to be a common thread here. You'll notice there is never a mention of Valencia ever doing anything for herself; she always acts for the good of the speaker or simply does what he wants. Since all of these events are described in the past, maybe the speaker is trying to either forget about or overcome the guilt he feels for being—he probably believes—the sole cause of Valencia's bloody death.
Both of the first two verses have the same structure: two lines describing why the two lovers shouldn't be together, then the speaker having a display of passion that overrides reason. For example, the first verse tells us that Valencia, in the present, "belong[s] to the gang" and "can't break away" but the speaker's "hands on [his] heart" show his desire for her to try to be with him. The second verse explains in more detail why the two can't be together, but the speaker tries to overcome this by "shout[ing] out [his] love to the stars."
How exactly do these images of hopeless love fit with the present tense image of her "blood still warm on the ground?" Well, they display the two most immediate emotions the speaker needs to deal with: overwhelming love and soul-crushing grief. While trying to fight back feelings of guilt by placing them in the past, the speaker places the purity of his love and the sadness of his love's death in the forefront of his mind by putting it the song's present tense.
Also, by placing the beginning and ending of the love story in the present, they seem to happen at the exact same time. This fits well with the predetermined tragic ending that we get with stories like this.
The future tense only comes up in two places: in the bridge to the chorus ("we'll go, we'll go") and when the speaker swears, "I'll burn this whole city down." These lines show both a hope for an escape to a better life and the threat of revenge when those plans are destroyed.
Even though the speaker does switch to future tense "I'll burn this whole city down" in the middle of the chorus, it comes in a much more intense form in the last two lines of the song. By placing the lines of hope for the future—"we'll go, we'll go"— before lines recognizing Valencia's death—"with your blood getting cold on the ground"—and then finishing with a threat—"I swear to the stars / I'll burn this whole city down"—we see a very quick progression of the speaker's emotions from something like romantic fantasy, to recognition that Valencia is dead, to full-fledged anger.
The fact that the future is used for both the fantasy and the oath of revenge shows how quickly and violently plans can change.
Essentially, this song creates a map of a mind twisted by a wide range of emotions. Guilt is in the past tense; love and grief are in the present tense, since they're the primary emotions driving the song; and hope and anger are in the future tense, showing that the speaker has a lot more to work through as he deals with the tragic events that he set in motion.
Don't take our word for it, though. Do you have a better explanation?