Green’s Dictionary of Slang

up the pole adj.1

[note late 19C US milit. up the pole, sober, ‘military’ and within regulation; the pole was the flagpole bearing the nation’s emblem]

1. [late 19C–1900s] (US) teetotal.

2. [late 19C–1920s] (also up the poll) drunk; thus half up the pole adj., tipsy.

3. [late 19C+] wrong, in error, in trouble, facing difficulties.

4. [late 19C+] insane, eccentric.

5. [1910s] bankrupt.

In phrases

get up the pole (v.)

[late 19C–1900s] to be approaching drunkenness.