Mass. Gen. Laws ch. 56 § 37
No member of the general court or paid officer or employee of the commonwealth shall promote or oppose, for a valuable consideration other than reimbursement for expenses actually incurred, the acceptance by the voters of any political subdivision of the commonwealth of any law conditioned to take effect therein upon such acceptance, or of any law or proposed law or constitutional amendment submitted under Article XLVIII of the amendments to the constitution, or an expression of opinion by the voters on any question of public policy.
Any person taking or giving employment in violation of any provision of this section shall be punished by a fine of not more than one thousand dollars or by imprisonment for not more than one year, or both.
Mass. Gen. Laws ch. 56, § 37