How to defend as Poland?

[GAGA Extrem]

In HOI2 it was possible to dig in in Warsaw with level 10 forts, but I doubt that this is doable in HOI3.
...anyway, I will give it a try and report back.

edit: Nah, won't work, NU will force you to surrender if you only hold Warsaw.

 

[GAGA Extrem]

It is possible to hold Warsaw with forts + 5 corps of INF/INF/TD/ENG. Unfortunately, you need 72 national unity - in theory you can reach that in 1939 by boosting it with spies, but a single -unity event will make defeat certain...