Dispositive

We were unable to produce any dispositive evidence to support our case.

Source: wiktionary

...the acquittal of the respondent on the charge of sexual assault causing bodily harm is not dispositive of the question of whether he used an object "in causing... injury" so as to make that object a weapon.

Source: wiktionary

The problem—or one of them, anyway—is that customers hate dynamic pricing almost as much as they hate normal price increases. […] But as it stands, dynamic pricing is largely regarded as legal, as long as sellers don't use protected characteristics such as race or gender to determine what buyers will pay. The algorithmic nature of dynamic pricing also gives sellers plausible deniability; who's to say which data points were dispositive? The main risk for retailers is one of perception.

Source: wiktionary

Controversies about his past loutishness should not be dispositive when deciding whether he should be confirmed. There are ample other reasons to reject his nomination.

Source: wiktionary