Union workers at John Deere plants in two Iowa cities have authorized a strike. The authorization does not mean a strike will occur, but allows the union negotiating team to call one if contract negotiations break down. The United Auto Workers union and Deere officials have been negotiating on a new contract for nearly 27-hundred workers since last month. Union members gathered in Cedar Falls and Dubuque on Sunday and voted in favor of the strike authorization. Results of the vote were announced on Monday. The current six-year contract, which covers U-A-W workers in Waterloo, Dubuque, Des Moines, and Ottumwa expires at midnight next Tuesday.