Montgomery County school board member Phil Kauffman. (Bill Mills/Courtesy of the Kauffman campaign)

IT WAS the very slightest of declines, but the dip in the four-year graduation rate for students in Montgomery County has unsettled the high-performing school system. In a district accustomed to seeing the rate go up each year, the 0.4 percent decline in students getting their diplomas between 2014 and 2015 underscores the challenges that confront Maryland’s largest school system. “Tipping point” is the phrase used by some officials in talking about the system’s future, which is why upcoming elections for the school board are seen as critical.

After a period of uncertainty that followed the ouster of Joshua P. Starr as superintendent, Jack R. Smith took over the 156,447-student system in July, and early reviews are promising. He is focused on improving outcomes in classrooms and has made clear that it is time to not just talk about the achievement gap that separates minority students from their white peers but to bring real urgency to solving the problem. He needs space and support to do this important work, including from a school board that understands its role is to make sure he does his job rather than to usurp it.

Three seats on the eight-member board will be filled in the nonpartisan elections Nov. 8. All candidates, even those running from particular districts, are elected countywide.

The at-large race features two strong candidates with incumbent Phil Kauffman being challenged for a third term by retired school principal Jeanette Dixon. Ms. Dixon, who had a standout reputation as principal of Paint Branch High School, certainly understands the school system and is admirably committed to closing the achievement gap, but Mr. Kauffman is the better choice at this critical time. Of all the members of the board, he is the most knowledgeable about the budget and has proved to be a valuable — and stabilizing — resource to other members.

The clear choice for the 4th District seat being vacated by Christopher S. Barclay is parent activist Shebra L. Evans. She brings years of experience volunteering in her daughters’ schools and at the county level, including as co-leader of the African American Student Achievement Action Group. She has keen insights into how to engage parents from diverse backgrounds, and her commitment has been unflagging, even after losing a school board race two years ago. Her opponent, accountant Anjali Reed Phukan, cannot match her in knowledge or experience.

In the 2nd District, incumbent Rebecca Smondrowski is being challenged for a second term by financial adviser Brandon Rippeon. Ms. Smondrowski has had a spotty first term, including questionable judgment in her use of district-issued credit cards. But she is the better choice over Mr. Rippeon, who ran against Rep. Roscoe G. Bartlett in the 2012 Republican primary and has had scant involvement with educational issues. Ms. Smondrowski has emerged as an advocate for children with special needs, so we hope she can learn from her missteps to become a more effective member of the board.