Abortion is the worst issue, as it pits the basic right of one person, incapable of defending himself or herself, directly against the rights of another. It's amazing how politicians of left and right never seem to have a problem finding a nice comfortable spot to park their philosophy, and then spout the talking points they've adopted ever afterwards.
The right to life is pretty paramount. But it's a good idea to reflect, every so often, that there are sympathetic and powerful stories on the other side of the question. (Note -- this is not the usual sob story about wire hangers and desperate women in back allies.)