When a defendant's requested exculpatory evidence is destroyed by the government prior to trial, should the trial proceed?

QUESTION(S) PRESENTED 1.) When a defendant in Federal Criminal Court proceedings requests to review, prior to trial, the evidence that is in the government's possession that is used against him, and when that evidence is singularly important to him because that evidence may be impeaching/ exculpatory, and when that evidence is destroyed prior to trial while in the government's possession and/or care, may the trial go on without the requested evidence, even if the evidence has been destroyed by the government? 2.) Is the government to be held responsible for destroying the said evidence prior to trial—evidence that may favor the defendant? 3.) Should the convictions that were rendered by such a compromized trial be vacated/dismissed or set aside? 4.) In a criminal case that is headed for trial, is it lawful and/or right for either party to remove and/or destroy evidence, prior to trial, in order to gain a legal advantage in/for the outcome of the trial, either intentionally or inadvertently? . PAGE I