My Catholic friends fall into one of two categories: Democrats and others. The Democrats are all voting Democrat because of something called "the seamless garment." The others are voting based on Catholic non-negotiables.
Without going into too much detail, the concept of non-negotiables is mentioned in Pope Benedict XVI's Sacramentum Cartatis. It basically says that there are some issues that are just wrong. You can't support them, even for the sake of doming some other good. These issues are the right to life, marriage and the family, and religious liberty.conscience rights. The idea is not that other issues aren't important, but that these issues are so fundamental to every moral good that support for them is abhorrent to morality.
The seamless garment theory was created by Cardinal Bernardin in 1984, and says that everything is connected, as are the threads in a single piece of cloth. This is, of course, true, and the idea of the seamless garment was to ground other issues, such as concern for the poor, peace, human rights, into a right relationship, all based on the fundamental rights mentioned above (aka non-negotiables). The problem is that it has been inverted by some Catholics to claim that all issues are morally equivalent because they are interrelated. This gives some Christians the notion that issues like immigration or the death penalty, for instance, are as important as abortion or euthanasia.
Of course, that is not what the seamless garment is about, but I thought it would be interesting to look at voting issues in terms of both the correct seamless garment theory and the distorted popular misconception of the seamless garment theory. Where do the parties stand? Is there a reason to vote Democrat under the seamless garment misconception?
Abortion
The Democratic party and the Biden/Harris ticket are not only in favor of legalized abortion, they want to support and increase it, both in number of abortions and in type of abortions. Making Roe v. Wade law, using tax payer funding to pay for abortions, making abortion part of foreign aid and coercing foreign countries to relax their own abortion restrictions will all increase the numbers of abortions. They have also called for eliminating all restrictions on late term abortions, allowing abortions for any reason and at any stage in pregnancy, even up to (and possibly after) birth and denying health care to already born babies who are not "wanted." No matter which criteria you use, this is a reason not to vote Democrat.
Transgender
Pope Francis, when asked what the preeminent issues for voting were, replied that abortion was preeminent, but it wasn't the only serious issue - he mentioned "transgender" as another extremely important issue. The Democrats and Biden/Harris have called for expansion of transgender "rights" by saying that transgender people must be allowed to choose to compete in any gender's sports leagues, shower and change in and gender's rooms, and force individuals and businesses to recognize the gender they choose. Biden has called for children as young as eight to choose their own gender without anybody being able to deny them. No matter which criteria you use, this is a reason not to vote Democrat.
Religious Liberty/Conscience Rights
Democrats have called for an end to religious "exceptions" and a repeal of the Religious Freedom Restoration Act. Biden has said he plans to prosecute the Little Sisters of the Poor over their refusal to pay for abortifacients. No matter which criteria you use, this is a reason not to vote Democrat.
Other non-negotiables
To keep this short, let's just say that on fetal tissue research, same sex marriage, school choice, parental rights, etc., no matter which criteria you use, these are all reasons not to vote Democrat.
Racism
The Democratic party is the party of racism. From the KKK to segregation, the Democratic party has opposed every piece of civil rights legislation. Harris aggressively prosecuted minorities, and even withheld information that might have freed inmates. Harris' family owned slaves. Biden authored a crime bill which gave lengthy prison sentences to minorities who committed minor offenses. Biden has made numerous disparaging comments about blacks. Many of the parties policies are racist, or support racist organizations, like Planned Parenthood, which was created to reduce the population of minorities, and still does through aggressive advertising aimed at them, and by placing abortuaries mainly in minority populated areas. No matter which criteria you use, this is a reason not to vote Democrat.
Immigration
The Democratic party favors open borders and non-enforcement of immigration laws in the US. This policy has been disastrous for immigrants, exposing them to criminals and sacrificing their safety. A recent study showed that 80% of all women who entered the US illegally were sexually assaulted in the process. In addition, human trafficking (aka slave trading), drug trafficking, and weapons trafficking are all enabled by the Democrats' policies. It was Democrats who "invented" separating children from parents and keeping them in cages at the border. No matter which criteria you use, this is a reason not to vote Democrat.
Climate
The Democratic party favors shutting down the US fossil fuel industry. This ensures that all the fossil fuels used will be environmentally dirty, and extracted without benefit of US environmental protections. In addition, they want to mandate solar and wind power. Both of these technologies are destructive of the environment, and not sustainable. Because they are intermittent, they do not reduce the need to have fossil fue powered backup plants. Because they are diffuse, the amount of land that would need to be stripped to supply the energy needs of the US is four times the total land area of the US. The energy used to make a solar panel is close to the total amount of energy it will produce, and the materials used are toxic, and will eventually seep into ground water. No matter which criteria you use, this is a reason not to vote Democrat.
War
Despite lip service to peace, Democrats have not followed through. The Obama administration (of which Biden was a part) made unprecedented use of drone strikes, killing 3,500 people, including American citizens, without due process of law, or a congressional declaration of war. He ramped up military activity and broke agreements with our allies. Billions in cash were clandestinely delivered to enemies of the US. On the flip side, President Trump has been nominated four times for the Nobel Peace Prize for brokering peace in the Middle east, in Europe and Africa. The war in Afghanistan is finally coming to an end under President Trump. No matter which criteria you use, this is a reason not to vote Democrat.
Law and Order
As a senator Biden pushed for a crime bill that directly led to the unconstitutional "stop and frisk" policy, and directly led to the current crisis of minorities in prison. He is (finally) under investigation for his "quid pro quo" deals with Ukrainian officials to get his son a job, and to interfere in criminal investigations into his dealings. Biden and Harris have refused to condemn burning and looting in
our cities (in fact, Harris said that the looting "should continue").
There was the weaponization of the IRS under the Obama
administration, the weaponization now of the media and social media,
Benghazi, Fast and Furious, etc. Harris refused to look into credible evidence of trafficking in human organs by Planned Parenthood, and instead colluded with them, took money from them, and prosecuted the journalist who uncovered their crimes. She withheld evidence that could have cleared two black men on death row. No matter which criteria you use, this is a reason not to vote Democrat.
Civility
One reason I have heard is that the Democrats are "civil" unlike President Trump. So let's look at how civil they are. Consider the Kavanaugh hearings, the Clarence Thomas hearings, etc. - they even invented a word "borking" for what the Democrats did to Supreme Court nominee Bork. They repeatedly called the president names, called him racist, despite a lack of evidence. In the first debate, Biden interrupted the president many times, calling him a "clown" and other names. Half of Americans have been called "deplorable" and "racist"... I could go on, but I think it is clear that no matter which criteria you use, this is a reason not to vote Democrat.
Health Care
The Democrats favor a return to Obamacare. The problem is that Obamacare doesn't solve any problems, but rather, institutionalizes them in government bureaucracy. In other words, instead of making drugs cheaper to manufacture, or regulating drug profits, it merely forces everyone to share the cost. From a Catholic perspective this goes against the principle of subsidiarity, that problems are best solved locally, not in a one-size-fits-all approach. It also doesn't make sense from a purely secular perspective. Lastly, it is not economically feasible. Obamacare worked for a few years because parts of it had their costs deferred to future years. In the next few years, as those costs kick in, premiums will become even more astronomical. The problems that it claims to solve - uninsured people, preexisting conditions - were either not actual problems, or have already been solved in other (better) ways. Jesus calls us to care for the sick. He does not call on us to take money from our neighbors to pay for it. No matter which criteria you use, this is a reason not to vote Democrat.
Voter Suppression
The Democratic party is the party of voter suppression, with a history that goes all the way back to Jim Crow laws, poll tests, etc. Today Democrats claim that voter ID laws are voter suppression, based on the racist theory that minorities aren't capable of getting government ID, yet they don't consider it suppression to require government ID to driver, receive government benefits, health care, etc. What they are pushing is lax election laws that encourage fraud. Voter fraud is voter suppression, since every "extra" vote cast nullifies the vote of a real voter who voted the other way. Given that minorities are minorities their votes are more easily nullified by voter fraud, so actually voter ID laws would help ensure minorities votes counted. No matter which criteria you use, this is a reason not to vote Democrat.
Death Penalty
Yes, the party platform states that Democrats oppose the death penalty, which takes the lives of about 20 convicted criminals per year in the US. Republicans are split on this issue.
Conclusion
In short, there is no issue, other than perhaps the death penalty, where the Democratic party does not directly go against Catholic teaching or the good of society. Even if you say all these issues are equivalent in moral value, the death of 20 people does not add up to the rest of the issues. Abortion alone kills 75 million human beings every year.