At the urging of a group of nurses, Governor Tom Vilsack and half of Iowa’s legislators have pledged to demand that presidential candidates provide answers to health care questions. Sarah Swisher, a nurse at University Hospitals in Iowa City, was among 20 nurses who’re lobbying at the statehouse Tuesday.Swisher says it’s important to ask the candidates not only how they plan to improve the nation’s health care system, but how they’d pay for it.The Iowa Nurse Alliance has formed a group called “Iowa for Health Care” with the goal of pestering the presidential candidates to commit to increasing access to quality, affordable health care as well as finding ways to control costs.