Some critics believe we should grapple with the text only and not rely on information from the poet's life, but I think we should use all the help we can get. So here's some help:
Philip Levine
editing back, now at work:
Knowing that Levine's early work was metrical and short-lined--and seeing that this is both--gives me a clue that this poem is from that early period and is one of those poems about being trapped in a murderous system. I think that read works. The title, while it does serve to gather the images, is a red herring.
I'd say this is about an Everyman--including the poet. It's spoken in a time when there was an unpopular war on for which men were being drafted, which makes the miltary buzz-cut references live ones in readers' minds. "In through the transom" isn't literal, but a reference to every person's sense that he's not here legitimately, that he's going to found out and prosecuted, that the world has it in for him. The rest of the images and allusions fit that read, I think.