In more than 16 years as a federal judge, Sonia Sotomayor has often sided with people claiming discrimination in education and employment. She's backed police and prosecutors over defendants. She's upheld assertions of free speech and religion.

Not easily pigeonholed, Sotomayor has also been part of rulings that go the other way.

In general, her rulings as a trial judge for six years and then as an appeals court judge since 1998 are in line with the liberal-leaning views of Justice David Souter, the man President Barack Obama has nominated her to replace.

Sotomayor's record indicates that her confirmation would not seriously alter the balance of power on a court that often splits along conservative and liberal lines on social issues.

Her opinions are clearly written and thorough, although she does not write with much flair. Sotomayor has been criticized by some conservatives for saying in a talk at Duke University that appeals court judges make policy, but her writings typically do not stray from the law.

Among the most contentious social issues is abortion, but Sotomayor has not been part of any major rulings on abortion rights. In 2002, she wrote an opinion ruling against an abortion rights group that had challenged a government policy prohibiting foreign organizations receiving U.S. funds from performing or supporting abortions.

In her opinion on the so-called gag rule, Sotomayor wrote that the government was free to favor the anti-abortion position when public funds were involved. President Barack Obama lifted the rule soon after he took office in January.

Abortion opponents reacted strongly against Sotomayor's nomination Tuesday. Charmaine Yoest, president of Americans United for Life, called Sotomayor "a radical pick that divides America."

The most controversial civil rights lawsuit of her time as a judge concerns the race discrimination claims of white firefighters in New Haven, Conn., a case the Supreme Court will decide in the next month.

In a one-paragraph opinion, she and two other judges on the 2nd U.S. Circuit Court of Appeals in New York upheld a lower court ruling dismissing the firefighters' claims. The case turns on promotion exams that the city threw out on the grounds that too few minorities scored high enough to be promoted.

The high court accepted the firefighters' appeals and, at argument in late April, appeared divided along ideological lines. The court is expected to rule by late June.

In many other discrimination cases, Sotomayor has sided with plaintiffs, including a black elementary school student who claimed his demotion from first grade to kindergarten was racial discrimination. Sotomayor, in a 1999 dissent, said that white children in similar situations received help, while the black child was not given an "equal chance."

She has favored claims brought by disabled people, those alleging age discrimination and women who said they were in hostile work environments. Yet she also said an international treaty governing air travel ruled out discrimination claims made by two African-American passengers.

In a religious freedom case, Sotomayor backed two New York state prison inmates in 1994 who practiced the religion Santeria and challenged a prison rule that banned them from wearing multicolored religious beads.

Sotomayor, ruling that the pair could wear the beads under their clothing, criticized as intolerable "distinctions which favor 'traditional' over 'nontraditional' religions."

She also struck down a White Plains, N.Y., law preventing the display of religious symbols such as a 9-foot-high menorah in a city park.

A former prosecutor, Sotomayor has frequently ruled against criminal defendants, including a sex offender who violated his parole by having in his apartment a book containing pictures and descriptions of sex between men and boys.

The Supreme Court in January essentially endorsed a 10-year-old pro-police position Sotomayor took in a case involving the search of a criminal suspect. In the high court case, the four liberal justices dissented.

But Sotomayor was reversed in an environmental case the Supreme Court decided in April. She supported environmentalists in ruling that the Clean Water Act does not allow cost to be used when deciding what technology would best minimize environmental impacts. Souter's view paralleled that of Sotomayor when the case reached the Supreme Court. There, the justices overturned Sotomayor's ruling, with Souter in the minority in a 6-3 decision.

The justices are considering whether to hear a case in which Sotomayor and two other judges upheld a New York state law banning the possession of "chuka sticks." At issue is whether the Second Amendment's guarantee of a personal right to have a gun restricts the power of state and local governments to regulate personal weapons.

The appellate judges said they were bound by an 1886 Supreme Court ruling, but acknowledged the high court could take a different view, particularly in light of last year's ruling that the Second Amendment protects an individual's right to keep guns at home for self-defense.

Sotomayor would have to step aside from the case if she is confirmed and it comes before the court.