BY SENATOR AMY KLOBUCHAR Medicare has been a great American success story, protecting the health and financial well-being of millions of senior citizens. It’s an American promise that should never be broken. A part of that promise is keeping prescription drug prices affordable for our seniors. When Medicare Part D was created in 2003, its goal was to supply cheaper prescription drugs to senior citizens. Ten years later, it is time to make improvements to this program to ensure we are meeting that goal.