Classic Anabaptism took a strong and pretty consistent position regarding the discontinuity between OT ethics and NT ethics. And that informed their pacifism. They regarded OT warfare, self-defense, and capital punishment, as an obsolete paradigm.
Contemporary Anabaptists are pacifists, but unlike old guard Anabaptists, many contemporary Anabaptists see more continuity between OT ethics and NT ethics when it comes to "social justice" issues like immigration and welfare for the poor.
That, however, means they can't erect a wall between the laws of OT warfare, self-defense, capital punishment, and NT ethics. They run the risk of making ad hoc exceptions. So their position is more precarious.