If one party be permitted, for any reason, to introduce inadmissible evidence, may his opponent counter with like evidence to offset any· advantage the former may have obtained? Or, as Dean Wigmore puts it: "Does one inadmissibility justify or excuse another?"
The problem is again brought to notice by the decision of the Iowa Supreme Court in the recent case of Maasdam v. Jefferson County Farmers' Mutual Insurance Association. In that case the lower court was reversed because it refused to permit the defendant to introduce evidence as to the market value of the insured articles after plaintiff had been allowed to put in evidence on that point. The court declined to decide whether or not the evidence was admissible (admitting there was some basis for saying that it was) and held that, even if it were inadmissible, it should have been permitted to the defendant as it had been to the plaintiff.
Theodore R. Vogt,
EVIDENCE - CURATIVE ADMISSIBILITY,
Mich. L. Rev.
Available at: https://repository.law.umich.edu/mlr/vol35/iss4/8