The Missouri Supreme Court has upheld a law criminalizing low school attendance for parents.

Two single mothers from Lebanon, Mo., challenged the law after they were sentenced over their respective children’s absences.

Caitlyn Williams was sentenced to a week in jail after her daughter missed 16 days of first grade last school year, and Tamarae Larue was sentenced to 15 days in jail after her son missed 13 days of kindergarten. Larue instead agreed to serve two years of probation.

The pair sued the state, claiming the law is too vague and the school district could not prove the parents were to blame for the absences. The court ruled against them in a 6-0 vote, with one justice not participating.

“This nonattendance was not excused by any circumstance provided for in the statute,” Justice Robin Ransom wrote in the court’s opinion. “Given the notice provided to each parent and that each parent was in control of their young child, evidence existed to support the inference that each parent knowingly failed to cause their child to attend school on a regular basis.”

The parents based their challenge on the wording of the law, which requires students to keep “regular” attendance, though they said it was unclear what “regular” exactly meant. The court ruled that “regular” applied to the school district’s attendance expectations: 90 percent attendance. 

Excused absences — due to sickness, for example — counted toward that 90 percent mark, the court said. If Williams’s and Larue’s children’s sick days were not counted toward their attendance, they would have been higher than 90 percent attendance, the parents said. 

“When measured by common understanding and practices, no Missouri parent would conclude attendance ‘on a regular basis’ means anything less than having their child go to school on those days the school is in session,” Ransom wrote.

Only a verified consistent illness or other long-standing condition or circumstance, communicated to the school in advance, would excuse that amount of absences, the court said.

The mothers’ attorney declined The Hill’s request for further comment.

Updated at 11:42 a.m.