What was one reason the Massachusetts legislature opposed the Mexican war?

They opposed it because it was against a weak neighbor. They also believed that it unnecessary and without a justified cause, at an extreme cost of treasure.

Explanation:

Most Americans— both men and women—believed that a woman's place was in the private world of the home. Women who were active in abolition or other social reform movements believed that they had important contri- butions to make to American society. They began to demand rights as equal citizens.