x1=p1 uses/employs x2=p2=k1 (reason/justification/explanation/pretext/excuse) for/causing/permitting x3=p3=k2 (event/state); p1=x1 justifies x3=p3=k2 (event/state) via justification x2=p2=k1; x2=p2=k1 is the reason/justification/explanation/pretext/excuse for x3=p3=k2 (event/state) used by x1=p1 (justifier).
p3=k2 may not necessarily be caused by p1=x1. p1=x1 is simply employing a justification for p3=k2. This word refers to the employment of a justification, rather than necessarily proving or refuting causality. The justification p2=k1 used by p1=x1 may not necessarily reflect p1's true belief; p1 employs it regardless of sincerity.