Ok! I was clearly unaware about the abortifacient action of the pill. So apologies for calling others misinformed, when it was actually me who was such. Regarding the IUD, from webmd’s website (a better source than planned parenthood perhaps?)
http://www.webmd.com/sex/birth-control/intrauterine-device-iud-for-birth-control
Hormonal IUD. This IUD prevents fertilization by damaging or killing sperm and making the mucus in the cervix thick and sticky, so sperm can’t get through to the uterus. It also keeps the lining of the uterus (endometrium) from growing very thick.3 This makes the lining a poor place for a fertilized egg to implant and grow. The hormones in this IUD also reduce menstrual bleeding and cramping.
Copper IUD. Copper is toxic to sperm. It makes the uterus and fallopian tubes produce fluid that kills sperm. This fluid contains white blood cells, copper ions, enzymes, and prostaglandins.
The hormone dispersed by the plastic IUD Mirena is Levonorgestrel, which also happens to be the main ingredient in the “Morning After” Pill.
What we don't know is whether Santorum is ignorant of that also, or if he does know but believes it would be an unpopular stand.
If he is ignorant of the abortifacient action and becomes aware, how does that affect his stance on birth control? If if he knows, is he avoiding because it could be a political hot potato?