Remember that Delayed Ensoulment, no matter how popular it was (yes, St. Thomas personally held this theory to be true) was never an official Church teaching.
I’m sorry, that simply is not true. In addition to St. Augustine, St. Jerome, and St. Thomas Aquinas, etc. we have Papal authority. For example, Pope Innocent III ruled in a case involving a monk and his lover. At that time, the term “animated” seems to have been adopted. At the beginning of the 13th century, he reiterated the distinction and set the time of ensoulment at “quickening”.
Pope Gregory XIV reaffirmed the “quickening” test in 1591, adding a hard deadline of just over 16 weeks.
Pope Pius IX dropped the distinction between “fetus animutus” and “fetus inanimatus” in 1869. But, he did not remove the prior teaching on delayed ensoulment. Quite the opposite, he stated that early in development, the fetus almost certainly was not animated, but that it did not matter because before then it was “anticipated murder”. The Catechism actually continued to carry the “animated” distinction until around 1913 (I’d have to check that date, but it was definately the 20th century).
Also, to say that abortion was not considered murder would be somewhat untrue. Read some of the quotations in this link. These Church Fathers seems to juxtapose “murder” and “abortion” quite a bit.
Again, we have popes saying it, not me. We have to be careful when we start pulling quotes because we are often not sure when abortion refers to later term abortions or abortion in general. I was surprised when I first started reading early Latin writings in earnest. A pair of very popular ‘pro-life’ quotes from Tertullian’s treatise on the human soul do seem clearly anti-abortion, but sandwiched between them is a gruesome description of a primitive partial birth abortion which Tertullian describes as inarguable moral, a “necessary cruelty”.
Also, you’ll often find masterbation and oral sex referred to as “murder”, depending on the particular age of the text.
It would be very untrue to claim that the Church was ever pro-choice . That has never been the case that we I can determine (and Pope John Paul II asserted the same in Evangelium Vitae). Jesus was born into a surprisingly pro-life culture with regards to abortion and earliest Church writings seem to indicate that, unlike purity laws, gentile converts were expected to follow suit.
However, it would also be untrue to claim that early abortion (prior to quickening) was not treated less greivously than late term abortions. That does not mean that it was not a mortal sin, just that, at various points in time, it was treated with less gravity. We can see this in things like Penitentials from the 7th and 8th centuries. Murder typically carried a pennance of 20 years to life. Oral sex a pennance of 10 years. Early abortion just 120 days.
In general, sterilization was typically viewed much more harshly because abortion represented a one time interruption to reproduction, while sterilization was forever. But I don’t see why Catholics should be alarmed because the perceived gravity of different mortal sins has changed over millenia. That is part of the reason we have a Magesterium.
The only ‘inconsistancy’ that I can see in Church abortion history is that our ban on abortions of medical necessity is relatively new. That is, we can find seeming permissiveness for abortions to save the life of a mother going right back to the time of Jesus. As late as 1869 the Church was declining to rule on the matter. It wasn’t until 1884 and 1889 that the Church specifically prohibited it. Frankly, the matter does not seem to really be settled yet. The Church seemingly ruled on ectopic pregnancies in 1902, but such pregnancies are frequently terminated in Catholic hospitals under various theological arguments (ex. ‘Double Effect’) today.
Personally, I don’t see it as truly being inconsistant. The Church didn’t obviously ‘switch’ positions. It seems more accurate to say that it declined to rule one way or another until the right moment in time. Again, a benefit of having a Magesterium.
Sorry to go on an on. I became interested in the subject when it struck close to home and have now been studying it for a number of years. It seems to upset some Catholics, but I actually think that, in context, our history enhances our ‘pro-life’ credentials.