Why intervene in Poland before helping Spain?

Why should Germany back one Polish faction before sending volunteers to Spain?

The proposed partner is considered easier to pressure into giving up territory. The opposing faction is expected to seek British, French or Russian backing.

Germany is urged to address the Polish conflict before sending volunteers to Spain. The preferred Polish faction is considered easier to pressure into giving up territory later. Its opponent is expected to seek help from Britain, France or Russia. Backing a faction now is therefore treated as preparation for later territorial demands. That calculation belongs to the game's alternate political paths.