Me. Rev. Stat. tit. 24-A, § 2507

There shall be a provision that the policy shall be incontestable after it has been in force during the lifetime of the insured for a period of not more than 2 years after its date of issue, except for nonpayment of premiums and, at the insurer's option, provisions relating to benefits in the event of total and permanent disability and provisions granting additional benefits specifically against death by accident or accidental means.