Mont. Code Ann. § 85-7-2137

In the event that for any reason a special tax or assessment provided for cannot or may not be levied and collected in time to meet any interest falling due on any bonds issued, the board of commissioners shall provide for and pay such interest when due, either out of any of the funds in hand in the treasury of the district not otherwise appropriated or by warrants drawn against the next district tax or assessment levied or to be levied. These warrants shall be in addition to those mentioned in 85-7-2001.