A Thin Red Line

I have traced the phrase "thin red line" back through Kipling to its origin. Needless to say, it appears twice in Poul Anderson's works:

"A nineteenth-century Britisher, competent but with elements of Colonel Blimp (scroll down), unrolled a map and discoursed on his aerial observations of the battle. He'd used an infra-red telescope to look through low clouds. 'And here the Romans stood -'
"'I know,' Everard said. 'A thin red line.'"
-Poul Anderson, "Delenda Est" IN Anderson, Time Patrol (Riverdale, NY, 2010), pp. 173-228 AT 8, p. 222.

So now we know. The Romans were unable to see what was above those low clouds.... "Colonel Blimp" wants to catch the Neldorians - which would have made for a very different conclusion for "Delenda Est" - but Everard pulls rank on him.

In another universe, a magical sword discourses:

"'There we stood, a thin red line - No, I'm mixing my epochs, damme.'"
-Operation Luna, 22, p. 205.

After centuries in England, the sentient Scandinavian sword has become acculurated with a "Colonel Blimp" personality.