This argument presumes that the right to life of the unborn child is the decisive issue for the voter. I will summarize the points covered in three magazine articles, which articulate the No and Yes responses to this question:
Is a Catholic morally obliged to vote for the Republican candidate?
William T. Cavenaugh, “Electing Republicans has not Reversed Roe v. Wade. It’s Time to Change our Strategy“
I. The history
The Supreme Court has had a majority of Republican-appointed Justices for the past fifty years. Both Roe v. Wade and Planned Parenthood v. Casey (which upheld Roe and required that the government impose no ‘undue burden’ inhibiting the supposed right to an abortion) were decided by courts with large Republican-appointed majorities.
The abortion rate has declined steadily, with no significant difference between Republican and Democratic presidential administrations.
II. The Supreme Court is unlikely to overturn Roe, no matter who the justices are.
Republican George W. Bush appointed Catholic John Roberts to the court. Roberts immediately became Chief Justice when the previous chief died while Roberts’ nomination was pending, in 2005. This past June, Roberts endorsed the principle of stare decisis in abortion cases, in Medical Services v. Russo. (Stare decisis means precedent is decisive.)
III. Political power should not be the pro-life movement’s chief goal.
Cavenaugh writes: The one strategy for reducing abortions that has been proven to work runs through love, not power: support for women who may not feel able to carry a pregnancy to term. This requires not blind allegiance to a political party but the promotion of a culture of life. For years, some in the pro-life movement have struggled to change the perception that opposition to abortion is about control over women. Hitching the pro-life cause to a president who has bragged about sexually assaulting women can only turn people away. The taint of Mr. Trump could well do irreversible damage to the pro-life movement and to the church itself, especially among the younger demographic.
Trent Horn, “Why Pro-Lifers Shouldn’t Give up on the Supreme Court,” and Richard Doerflinger, “Four Reasons a Democratic Administration Would Mean More Abortions.”
I. The history argument is not decisive.
Abortion was not a campaign issue for the Republican presidents who appointed the majority in the Roe decision. Opposition to pro-life judges by Democratic Senators has led to the nomination of justices with no paper trail, like Roberts. Republican presidential administrations, with large Republican Senate majorities, will lead to the appointment of genuinely pro-life justices.
II. Stare decisis does indeed control Supreme Court decisions, but not forever.
When the public mind has clearly shifted, the Court overturns previous rulings, as with slavery, segregation, and homosexuality. The Roberts court upheld the partial-birth abortion ban in 2007, restricting access to abortion.
Horn writes: If Roe were overturned, Democrats would do everything in their power to reinstate it (whether by a future court case or a constitutional amendment). Pro-life Republicans would be able to rely on the votes of their pro-life constituents—to prevent a new Roe nationally and to enact legal prohibitions of abortion on the state level—just as Democrats have been able to rely on the continuing support of pro-abortion voters during the Roe era.
III. ‘Incremental’ pro-life laws, bans on public funding for abortion, and pro-life pregnancy centers do work in reducing abortions.
Biden and Harris support a transition from “pro-choice” to abortion as essential healthcare, which would exclude all conscientious objection to abortion.