President George W. Bush on Tuesday scored one of the biggest political successes of his presidency when the US Senate confirmed his choice of a second conservative justice to the US Supreme Court, Justice Samuel Alito.

The victory will be welcomed by the president, whose second term has been marked by mounting pressure over Iraq, the war on terror and failures to push through several key domestic policy initiatives.

Mr Alito, who was confirmed by a mostly party-line vote of the full Senate, was expected to be sworn in immediately so he could attend the president?s state of the union speech last night.

He watched the confirmation vote with the President at the White House, underlining the political nature of the appointment process.

Mr Alito replaces Justice Sandra Day O?Connor, who often held the balance of power on the evenly divided nine-person high court, especially on social issues.

His appointment is likely to shift the court slightly to the right, particularly on contentious issues such as abortion. The Senate voted 58-42 to confirm Mr Alito, after a highly acrimonious debate that included a last-ditch effort to use the procedural move known as a filibuster to block the nomination. All but one of the Senate?s 55 Republicans voted for him.

Mr Alito won six more votes than Justice Clarence Thomas, the last such controversial nomination, but received 20 votes fewer than Chief Justice John Roberts, a conservative who was confirmed in September with half the Democrats supporting him. Mr Alito got only four Democratic votes.

Most Democrats opposed the nomination, on the grounds that Mr Alito, who has been a federal appeals court judge for 15 years, had shown hostility to civil rights, to women?s reproductive choice, and excessive deference to the executive branch of government.

?We need to ask whether a Justice Alito will serve as an effective check on a swaggering president,? said Senator Harry Reid, the top Democrat in the Senate, before casting his vote against the nominee.

?There is a grave risk he carries a legal agenda, one that he will bring with him to the Supreme Court,? said Senator Frank Lautenberg, a Democrat who represents Mr Alito?s home state of New Jersey.

Republicans countered that Mr Alito was a highly qualified jurist with a reputation for fairness and even-handedness.

They said that justices should be chosen according to their qualifications, not their politics.