Contract talks between the United Auto Workers union and General Motors broke off Sunday and haven’t resumed, meaning the union’s first national strike since 2007 is very likely. GM’s 49,200 UAW members are scheduled to go on strike at 11:59 p.m. unless an agreement is reached on a new four-year contract. GM says it has made substantial offers, but union officials say they’re far apart on wages, health care, use of temporary workers and other major items.