Me. Rev. Stat. tit. 15, § 1315

In all criminal trials, the accused shall, at the accused's own request but not otherwise, be a competent witness. The accused may not be compelled to testify on cross-examination to facts that would convict or furnish evidence to convict the accused of any other crime than that for which the accused is on trial. The fact that the accused does not testify on the accused's own behalf may not be taken as evidence of the accused's guilt. The spouse of the accused is a competent witness except in regard to marital communications.