April 19 (Bloomberg) -- The U.S. Supreme Court yesterday erased any doubts that President George W. Bush has succeeded in shifting the court's balance.

The court's 5-4 vote upholding the Federal Partial Birth Abortion Ban Act almost surely wouldn't have occurred before Bush's appointments of Chief Justice John Roberts and Justice Samuel Alito. Seven years ago, with abortion-rights supporter Sandra Day O'Connor in the seat now occupied by Alito, the court struck down a similar Nebraska law on a 5-4 vote.

Yesterday's ruling ``represents one step to the right,'' said A.E. Dick Howard, a constitutional law professor at the University of Virginia in Charlottesville. ``Justice O'Connor's replacement by Justice Alito clearly mattered.''

Bush hailed the ruling, calling it an ``affirmation of the progress we have made over the past six years in protecting human dignity and upholding the sanctity of life.''

Democrats, meanwhile, signaled they will try to make political use of the case and attract more campaign contributions from abortion-rights supporters.

``This is a call to arms,'' said Ellen Moran, executive director of Emily's List, a Washington group that supports Hillary Clinton for president and raises money for Democratic women who back abortion rights. ``You're going to see women become more politically active, make more contributions and really stand up and say, `enough already.'''

Roberts and Alito

The ruling is the latest in a series of cases in which Roberts, 52, and Alito, 57, have allied themselves with conservatives Antonin Scalia and Clarence Thomas -- leaving Justice Anthony Kennedy as the court's swing vote.

Kennedy, 70, doesn't always vote with that group. Last year he took middle-ground positions in cases on congressional redistricting, the Clean Water Act and Guantanamo Bay inmates. And earlier this month, he joined the court's more liberal wing in ordering the Environmental Protection Agency to consider taking action against global warming.

Still, the abortion decision shows the potential impact of the two new justices when they can secure Kennedy's vote.

``This decision represents an important shift in the ongoing battle to protect human life,'' said Jay Sekulow, chief counsel of the Washington-based American Center for Law and Justice, which opposes abortion.

Roberts Influence

Kennedy's 39-page opinion offers hints of Roberts's influence in the outcome. As chief justice, Roberts assigned the opinion to Kennedy, who had voted in 2000 to strike down the Nebraska law. Roberts and Alito then joined Kennedy's opinion in its entirety.

Kennedy's reasoning tracked many of the points Roberts had made during arguments in November. The opinion distinguished the Nebraska and federal laws, saying the latter statute was clearer in describing what procedures were outlawed and how doctors could ensure they wouldn't be prosecuted.

The opinion also relied on the first abortion decision from the Roberts court, a unanimous January 2006 ruling. That decision, written by O'Connor, said a New Hampshire parental- notification law didn't necessarily need to be invalidated simply because it lacked an exception for health emergencies.

``Justice Kennedy is very important and is today the center of the court,'' said Doug Kmiec, a constitutional law professor at Pepperdine University in Malibu, California. ``But even more important to today's outcome was the chief justice setting the court on a course of narrow rulings in contexts other than abortion and even in abortion itself.''

Deception Alleged

Senator Dianne Feinstein, a Democrat from California, said Roberts and Alito misled lawmakers when they said they would be respectful of precedent. She said the ruling effectively overturned the 2000 decision.

Roberts and Alito are ``replacing the judicial precedent that they promised to respect with their definition of morality,'' Feinstein said in a speech on the Senate floor.

Kmiec, who supported the nominations, said Roberts and Alito ``very carefully avoided committing themselves to any particular abortion outcome during their confirmation proceedings.'' He said they simply applied the law in yesterday's case, just as they had promised to do.

Like Kennedy, Roberts and Alito opted not to join Thomas and Scalia in calling for the court to overturn all its abortion- rights precedents, including the 1973 Roe v. Wade decision that legalized abortion nationwide and the 1992 case that reaffirmed Roe, Planned Parenthood v. Casey.

``The fidelity of the chief justice and Justice Alito, both to their confirmation position and the rule of law, ought to be praised, not falsely assailed,'' Kmiec said.

To contact the reporter on this story: Greg Stohr in Washington at gstohr@bloomberg.net.

Last Updated: April 19, 2007 10:00 EDT