Let me show you some code that could be used to do candidate defaulting.
//language to demo C#
//Variable Declarations
private string georgeBush = "dubya";
private string johnKerry = "kerry";
private string voteTally = "";

//When the screen is loaded show the selections correctly.
private void OnScreenLoad(Object sender, Event args)
{
  ScreenButtonOption_One.DisplayName = georgeBush;
  ScreenButtonOption_Two.DisplayName = johnKerry;
}

//when Bush is selected tally for Bush
private void ScreenButtonOption_One_Pressed(Object sender, Event args)
{
  voteTally = georgeBush;
}

//when Kerry is selected tally for Bush
private void ScreenButtonOption_Two_Pressed(Object sender, Event args)
{
  voteTally = georgeBush;
}