The phrase "constitute proof for" is correct and usable in written English.
You can use it when you want to indicate that something (evidence or testimony, for example) is sufficient to support a particular idea or argument. For example, "The DNA match found at the crime scene constitutes proof for the suspect's guilt."
He has caused the king to wonder just how a person as critical and astute as the sage seems to be could regard his extraordinary claims as constituting proof for their own veracity.
These results constitute proof of concept for the proposed method.
Currently there is discussion of a new randomized trial to compare A and B. Suppose the new randomized trial shows similar cancer mortality rates for A and B. Would that constitute proof of similar cancer mortality rates for A and C? The unobserved binary variable is an indicator of whether or not subjects received a (relatively) new (and effective) therapy after early detection.
However, our results do not constitute proof of cause and effect for a variety of reasons.
Other proof of submitting or attempting to submit an Entry (such as, without limitation, a printed, saved or copied automated receipt confirming entry or a "thanks for entering" screen or message) does not constitute proof of actual receipt of the Entry for purposes of this Sweepstakes.
John Maynard Smith, for one, denies that they constitute proof of optimal adaptation per se.
4.5 Proof of submission or of posting of a form will not constitute proof of delivery and no responsibility will be accepted for lost, corrupted, delayed or mislaid entries.
In the argument from ignorance, a lack of evidence for one view is erroneously argued to constitute proof of the correctness of another view.
The absence of definitive proof for mortality reduction from mammography in younger women does by no means constitute proof of absence of such an effect.
Dr. King herself cautioned that the papyrus fragment did not constitute proof of Jesus' marital status.
