If you can’t beat ‘em, get ‘em to join. That may be the thinking over at the American Federation of Teachers.

Long the vocal opponents of the charter school movement, the teachers’ union AFT Local 420 will announce Tuesday that they are embracing one such school: the Construction Careers Center high school, whose teachers will be joining the union as part of an agreement quietly reached last month.

AFT Local 420 will represent the roughly 30 teachers and aides working at Construction Careers, whose charter is sponsored by St. Louis Public Schools.

The Construction Careers Center, located at 1224 Grattan, just east of Lafayette Square and west of Soulard, was established as the first charter high school in the country focused on preparing students for jobs in the construction industry and has an 88 percent employment rate for its graduates. Teachers at the school make an average annual salary of around $42,000.