This is very clearly, to me, a song about loss from the effects of ideological war.
"Wide-eyed and up in arms"
This points to a cause pushing someone he cares deeply for the little brother) to spirited action.
"My little brother was a solemn one"
This "little brother" was dead serious in general, most likely his committment to the cause he had associated with.
"He always had his quiet corner."
He was susceptible to introspection, perhaps gentle of nature initially, but pushed to becoming radicalized by internal/external rationalization.
"Pride of my countrymen, my little brother will be born again"
This cause ended up being the death of his "little brother", be it war or otherwise. This same cause will convince others, in the future, to become inflamed by and die for this cause as well "Born again" refers to other peoples "little brothers" to become new soldiers, perhaps.
"Just give us back our quiet corner"
The singer clearly mourns the loss of his "little brother"; whether or not the cause is grand enough to be worth it, the price was high enough to mourn at present moment.
"Now go back to the other side of my bed. I'll go back to the place where you get started."
This is directed to the "little brother" who has passed. The singer hopes they will rest in peace; the singer will either take up the brother's cause or pick up the pieces that were shattered by this person's passing.
"And I'll sleep, just put the pillows under my head."
Ambiguously, this is either indication that the singer will attempt to realize his passed "little brother"'s vision, thus following in their footsteps, or that he will carry the memory of his "little brother" with him into the next day.
This is very clearly, to me, a song about loss from the effects of ideological war.
"Wide-eyed and up in arms"
"My little brother was a solemn one"
"He always had his quiet corner."
"Pride of my countrymen, my little brother will be born again"
"Just give us back our quiet corner"
"Now go back to the other side of my bed. I'll go back to the place where you get started."
"And I'll sleep, just put the pillows under my head."