Deep blue Massachusetts is far from the presidential campaign trail. But a high-stakes campaign has flooded the state with social media and television ads, pressing voters to consider a major change to the public school system widely seen as the nation’s best.

In Massachusetts, a generation of students has been required to complete standardized exams in English, math and the sciences to earn a high school diploma. The requirement is the capstone of a rigorous set of standards that have helped set the state apart from others on achievement tests.

On Election Day, Massachusetts voters will decide whether to change course.

A ballot measure known as Question 2 would eliminate the exams as a graduation mandate. If it passes, there would be no statewide requirements for receiving a diploma.

The proposal has provoked sharp divisions among Democrats, who control the state government.

The state’s teachers’ union, which spearheaded the ballot question, has poured millions into efforts to convince voters the exam shuts out teenagers who already have the odds stacked against them. They have pointed to research showing such mandates can push more disadvantaged students to drop out.

Several members of Congress like Representative Ayanna Pressley and Senator Elizabeth Warren, a former special education teacher, support the union, saying one test cannot measure all students’ skills.

Business executives and state leaders, including Gov. Maura Healey, also a Democrat, have urged voters to keep the test requirement, arguing the uniform standard sets one expectation for all students, regardless of their ZIP code. And The Boston Globe’s editorial board warned in grave terms that while Massachusetts schools “are the envy of the nation,” the effort “threatens one of the foundations of the state’s success.”