De or het non-agressie?

The correct Dutch article is:

de non-agressie

Rule Words ending in -tie and -sie: almost always de. See the rule

How to use non-agressie

the non-agressiede non-agressie
this non-agressiedeze non-agressie
that non-agressiedie non-agressie
our non-agressieonze non-agressie
your non-agressiejouw non-agressie
every non-agressieelke non-agressie
which non-agressie?welke non-agressie?
a big non-agressie / the big non-agressieeen grote non-agressie, de grote non-agressie