Just so we're on the same page with the "seamless garment theory."
Put simply, the Seamless Garment postulates that being pro-life involves not only fighting against abortion, but also against euthanasia, the death penalty, war, social injustice, anti-immigrant sentiment, and a host of other social issues that can also result in the death of human beings, whether directly or indirectly.
How did this theory make Catholics vote for abortion?
ok, the theory puts these on the same footing but they are not. Abortion and Euthanasia are intrinsically evil, that is always sinful. They are not the same, as the death penalty is biblical and is part of Catholic teaching. Francis says that today we are better able to incarcerate prisoners and the death penalty is not necessary. That may be true, but it does not make the death penalty intrinsically evil. According to previous theologians, war is sometimes just, not all the time, but sometimes, so that is not intrinsically evil.
Anti-immigrant sentiment is a red herring. There may be some extremists that are against all immigrants, but the overwhelming majority of conservatives are against the situation we have now in the USA, which is open borders. Jerusalem's walls were rebuilt. When the walls were down, it was desolate and unsafe, when the walls were rebuilt, the just could live safely. Open borders does not only allow immigrants to come into our country, but criminals and terrorists as well, so those that are against open borders are not intrinsically evil.
In the twenty first century, social justice has been used as and excuse to support socialism and communism, which are intrinsically evil and against church teaching. Liberation theology has been roundly condemned. Social justice has been the main virtue signaling cover for those that vote for politicians that support abortion and euthanasia. If you want to give to the poor, by all means do so and it is righteous to give alms, but don't shove some Marxist, Leninist, Maoist system down our throats and call it right and just. That system has been condemned by the Church and has lead to untold millions of deaths and persecution of the Church. Capitalism is no better as both try to replace God with economic issues. Fulton Sheen once said a communist is just a capitalist with no cash in his pocket; both want the same thing and are anti-Christ. Some politicians are Marxist/socialist, and voting for them for social justice reasons despite their support for abortion and euthanasia is probably the most unjust thing one can do.
Calling these things Pro-life is probably another red herring, as it distracts us from the truth. I do not call myself Pro-life. Salvation is not to be found on this Earth, and death is not something to be feared. To live is Christ, to die is gain. What does it profit a man should he gain the whole world, yet lose his own soul? Also, fear not those that can kill the body, but He who after He has killed the body is able to cast you body and soul into hell, fear Him. I am Pro-eternal life.
Abortion and Euthanasia are against God's law, are intrinsically evil, and those that do them or support them will be judged by God, unless they repent. The other acts may or may not extend human life, but at what cost? What would one say to God at the judgement? Yes Lord, I supported these politicians that make your law of no effect, but I supported helping people live a longer life on Earth.
Somehow I don't see that going well for that soul.
The seamless garment theory was used to equate intrinsically evil acts with those that are not always evil and use those not always evil acts as an excuse to support politicians that vote for abortion and euthanasia. That is the whole reason seamless garment was proposed by Cardinal Bernadine. I'll take a short life here with eternal life in Heaven over a long life on Earth with eternal damnation any day. Some people do not feel that way; the twenty first century mind set is to fight death at all costs without regard to the health of the soul. I am sad that people die, sure, but I am more grieved that many die outside of sanctifying grace by ignoring or deliberately countering the laws of God