October 16th, 1945
Dear Mr. Bloom,
As a scientist and one of your former constituents I urge you most earnestly to vote against the May bill for the control of atomic energy.  The haste with which the bill was framed and with which hearings were held and concluded is positively indecent, and an affront to all who are earnestly striving for a just and beneficent measure of control over this crucial discovery.
It is evident that the scientists who presented the world with this awful dilemma of destruction or immeasurable benefit, have not been adequately heard; it is evident that the control board under the bill might be made up entirely of industrialists whose intent might be to impede progress in directions contrary to their present interests; and it is evident that it would be exceedingly difficult to change the board appointed under the bill without long and involved legal action.
Mr. Bloom, your responsibility in this matter is an awful one, for which you have my full sympathy.  My only request is that you vote against this hasty action provided in this bill and so furnish the opportunity for heart-searching, disinterested, and united action after the truly exhaustive investigation demanded by the vast implications, national and international, of atomic energy.
Very truly yours,
Michael Heidelberger, Ph. D.,
Professor of Biochemistry, Columbia University,
Member, National Academy of Sciences,
Consultant to the Secretary of War.