WASHINGTON -- They're all younger than 55 and conservative enough to make a first cut. But the four judges who are apparently the finalists for President Donald Trump's second Supreme Court nomination are being measured against a set of questions going well beyond age and ideology.

Presidents weigh all sorts of considerations in deciding on a Supreme Court nominee, often beginning with the big question: Will the choice be confirmed by the Senate? Academic credentials, professional experience and sometimes even gender, race and geographical diversity all can be part of the equation.

The stakes are sky high for filling the opening created by Justice Anthony Kennedy's imminent retirement. The new justice has the potential to entrench conservative control of the Supreme Court for years to come.

Here are some of the pluses and minuses for each of the presumed leading candidates, in alphabetical order:

Amy Coney Barrett

Raymond Kethledge testifies during his 2008 confirmation hearing for the Sixth U.S. Circuit Court on Capitol Hill in Washington.C-SPAN ~ Associated Press

She is 46 and a judge on the U.S. Court of Appeals for the 7th Circuit.

If Trump is looking to make history, Barrett could have some appeal. If she's chosen and confirmed, it would be the first time four women would serve together on the nine-member Supreme Court. In addition, she is the youngest of the leading candidates, and Trump has said he wants his nominee to serve for decades. Barrett, a longtime law professor at the University of Notre Dame, also served as a law clerk to the late Justice Antonin Scalia, who is beloved by conservatives. And she recently made it through the confirmation process, with the Senate approving her nomination to be an appeals court judge in October. Three Democrats voted for her then.

But Barrett's recent ascension to the appeals court means she does not have the long, conservative record lawmakers on the right find reassuring. Barrett is also seen as a potentially divisive nominee because of statements she's made about her Catholic faith and about abortion. In her 20s she co-authored a paper stating Catholic judges, if they are faithful to church teachings, are "morally precluded" from enforcing the death penalty. At her recent confirmation hearing, however, she said it was never permissible for judges to "follow their personal convictions in deciding a case." More recently, she's written abiding by precedent is "not a hard-and-fast rule" in the Supreme Court's constitutional cases. Although the statement is undoubtedly accurate, it is likely to be seized on by supporters of abortion rights as they try to convince moderate Republican senators Barrett might vote to overturn the 1973 Roe v. Wade decision declaring a woman's constitutional right to abortion.

Thomas Hardiman

He is 52 and a judge on the U.S. Court of Appeals for the 3rd Circuit.

Judge Thomas Hardiman smiles during a 2017 meeting with The Associated Press in Philadelphia.Matt Slocum ~ Associated Press

Hardiman was a runner-up when Trump nominated Neil Gorsuch to the high court in 2017. He might appeal to Trump if the president is looking for someone from a blue-collar background. Hardiman was the first in his family to attend college, at the University of Notre Dame, then helped pay for his law school education at Georgetown by driving a taxi. Hardiman has some notable opinions in his 11 years on the appeals court potentially appealling to Trump, including upholding strip searches of jail inmates, even those arrested on minor charges, backing collection of genetic evidence from people at the time of their arrest and dissenting from a ruling upholding gun regulations in New Jersey.

Hardiman's judicial chambers are in Pittsburgh, where his wife comes from a family of prominent Democrats. He also was a colleague of Trump's sister, Judge Maryanne Trump Barry, who stopped hearing cases last year. Some conservative groups don't trust Barry because she wrote an opinion striking down a New Jersey abortion regulation in 2000, and they hope she has no influence over her brother's choice.

Brett Kavanaugh

He is 53 and a judge on the U.S. Court of Appeals for the District of Columbia Circuit.

Roughly 300 opinions in 12 years as a judge and a raft of legal articles and speaking engagements make Kavanaugh the most prolific of the prospective nominees. He is widely viewed as a skilled, conservative judge on what is often called the second most powerful court in America. His opinions include several dissents later vindicated by Supreme Court majority opinions. Kavanaugh, who worked on the investigation leading to President Bill Clinton's impeachment, later wrote he thinks presidents shouldn't have to deal with criminal investigations or civil lawsuits while in office -- a view Trump might find attractive. He attended Yale both as an undergraduate and law student, and served as a law clerk to Kennedy. He is active in his local Catholic church and as a coach for his daughters' basketball teams.

Amy Coney Barrett, United States Court of Appeals for the Seventh Circuit judge, speaks during the 2018 University of Notre Dame's Law School commencement ceremony in South Bend, Indiana.Robert Franklin ~ Associated Press

Some social conservatives fear Kavanaugh isn't committed to issues mattering to them, such as abortion. They cite a recent case involving a pregnant teenaged immigrant in federal custody. Kavanaugh would have delayed the teen's abortion, in line with the Trump administration's position, but another judge would have gone further and declared, as someone who is in the U.S. illegally, the teen had no right at all to an abortion. Kavanaugh's close ties to the Bush family, stemming from his five years in the White House under President George W. Bush, might not be a positive to Trump, who has sparred with the Bushes. Kavanaugh also was a clerk for Judge Alex Kozinski, who retired abruptly last year as allegations of sexual misconduct grew.

Raymond Kethledge

He is 51 and a judge on the U.S. Court of Appeals for the 6th Circuit.

Kethledge's 10 years as a federal appeals court judge give him a long record of conservative opinions perhaps making Trump and Republican senators feel secure about the kind of Supreme Court justice he'd be. He's written opinions siding against unions in a dues collection case, admonishing the IRS in a case about its targeting of conservative groups and approving broad access by the government to cellphone location data, an opinion overturned last month by the Supreme Court. He's also seen as a strong supporter of the Second Amendment.

Like Kavanaugh, Kethledge is a former Kennedy clerk and would no doubt cite the experience in attempting to appeal to moderates. Kethledge also has firsthand experience with Congress. For about a year and a half in the 1990s, Kethledge was counsel to Republican Sen. Spencer Abraham of Michigan. If Kethledge is the nominee, experience working for Congress could help in the customary courtesy visits to senators before a confirmation hearing.

At the same time, Kethledge left Washington to return to Michigan two decades ago. He probably has fewer friends in the nation's capital than Kavanaugh, but Trump may put value on the fact he's an outsider and less well known in Washington. In addition, Trump is thought to be looking for a nominee with superior academic credentials. That could be a problem for Kethledge if what Trump really meant was he wants an Ivy Leaguer, like the rest of the high court. Kethledge attended the University of Michigan for both undergraduate and law school.