If a condition precedent requires the performance of an act wrong in itself, the instrument containing it is so far void, and the right cannot exist. If it requires the performance of an act not wrong of itself, but otherwise unlawful, the instrument takes effect and the condition is void.
N.D. Cent. Code § 47-02-24
Illegal conditions void
Official source: North Dakota Legislative Branch. Reproduced from public-domain North Dakota statutes; confirm against the official source for the current text. Not legal advice.