The thief in this poem is sleep itself, and the speaker lies awake every night waiting for it to arrive. The twist is that the usual roles are reversed: instead of guarding against a burglar, the speaker is guarding against the very thing they most want. The weapon they brag about shrinks quickly. A "stout club" becomes "a stick," then "a rooster that never moves," a deflating joke that shows how little power the speaker has over their own body.
The tone is wry and tired. The speaker laughs at their own failed defenses, and the lines about the radio and the static capture the frustrating feeling of being close to rest but only getting noise. The ending is the neatest turn. Waking with a full bladder seems like the one thing that could rescue them, yet by then all they want is to let go and drift off. The mood is darkly funny, a little helpless, and very familiar to anyone who has stared at the ceiling at night.