Why are third trimester abortions controversial?

[Progressive Pessimist]

One thing I always like to point out when it comes to third trimester abortions is that they fall under the "three exceptions" rule that "moderate" Republicans like to espouse. Abortions in the third trimester are almost always conducted due to the life of the mother being in jeopardy. So whether they know it or not, some Republicans actually support them.