WASHINGTON -- The Supreme Court's just-completed term saw dramatic changes, with two new conservative jurists picked by President Bush and major rulings that rejected physician-assisted suicide and Bush's policies on Guantanamo military tribunals .
For the first time in more than 11 years, the court's composition changed, with Bush appointing John Roberts to succeed the late William H. Rehnquist as chief justice and Samuel A. Alito Jr. to replace Justice Sandra Day O'Connor, who retired.
Legal analysts said it is too early to say what influence Roberts and Alito, who both had solid ly -conservative voting records in the 2005-06 term, will ultimately have.
Others say the balance has already tipped .
``Americans' rights and liberties are already less secure after just one year of the Roberts court," said Ralph Neas of People For the American Way Foundation, a liberal lobbying organization.
He cited 5-to-4 rulings that said free speech rights do not protect government whistle-blowers, that allowed evidence apprehended when police enter ed a suspect's home without knock ing and announc ing their presence, and that limited the scope of the clean water law .
Analysts also said Justice Anthony M. Kennedy assumed a position of power at the center of the court, a role previously played by O'Connor. He often cast the decisive vote on a court split between four conservatives and four liberal justices.
``Justice Kennedy now holds the balance of power on a closely divided court," said Steven Shapiro of the American Civil Liberties Union.
He said Kennedy's vote may be more important on critical issues than those of Alito and Roberts.
Kennedy wrote the ruling that the Bush administration overstepped its authority when it barred doctors from helping terminally ill patients die in Oregon, the nation's only state that allows physician-assisted suicide.
He joined the four liberals in the 5-to-3 ruling that struck down the military tribunals Bush created to try Guantanamo prisoners suspected of terrorism .
Kennedy crafted the ruling that allows states to redraw congressional districts mid-decade for political gain, and his opinion controlled a major environmental ruling for a splintered court.
He wrote rulings that death row inmates can challenge the lethal injection method of execution and can get new hearings when DNA or other evidence later casts doubt on their guilt.
Although Roberts said at his confirmation hearings that he wanted to bring more unanimity and tranquility to the court, the justices remained split on criminal law cases, police practices, and the death penalty, analysts said.
``The court revealed through a number of rulings in capital cases that it is still deeply divided over whether and how it should be actively involved in the regulation of capital punishment," said Doug Berman, a law professor at Ohio State University.
Roberts is the first new chief justice in nearly two decades. As an indication of his inability to dominate the court's decisions in his first term, Roberts was a dissenter in rulings nearly as often as he was among the majority.
He did not take part in the court's ruling last week on military tribunals for Guantanamo detainees because he had ruled on the issue as a member of the federal appellate court.
And in cases pitting police powers against privacy rights, the justices often upheld the searches.
Roberts wrote rulings that bolstered police power to enter a house to break up a fight and that allowed statements given to police by arrested foreigners, even when they have not been told of their right to contact their consulate.
The justices adjourned for their traditional three-month summer recess and will return to the bench in October for the new term.
That term could be a blockbuster.
The court has on its docket hot-button social issues such as abortion and whether race can be used as a factor to decide which students can be admitted to specific public schools.