The Senate Judiciary Committee has begun a week of scrutiny of Judge Samuel Alito, President Bush's Supreme Court nominee, whose confirmation could shift the country's highest court decisively to the right.
The hearings began decorously as each member of the Republican-dominated panel made a statement, and the 55-year-old nominee delivered his introductory response. But from today, when detailed questioning begins, the sparks will almost certainly fly.
The hearings are likely to focus on two issues: the perennial argument over abortion rights, and the new debate over the extent of presidential powers. Judge Alito, a Catholic, has come under fire from liberals for his apparent hostility to abortion and his alleged deference to executive authority.
Appointments to the Supreme Court, of lifelong tenure, have always been of huge political significance. But in the bitterly polarised climate of today this one is particularly so.
The general view is that Judge Alito will be confirmed, albeit by a much narrower margin than the 78-22 vote which endorsed John Roberts last September as Chief Justice, to replace William Rehnquist.
Unlike Mr Bush's previous nominee, the largely unqualified White House counsel Harriet Miers, his competence is not in question, after 15 years on the federal appeals bench. Only last week the American Bar Association gave him its highest grading, pronouncing him "well qualified" to sit on America's highest court.
But there could be fireworks - and the stakes are much higher. Roberts-for-Rehnquist substituted one conservative for another, and did not change the balance on the court. Judge Alito would replace Sandra Day O'Connor, often the swing vote among the nine justices, and a reliable defender of abortion rights.
His confirmation would almost certainly shift the Court rightward. Democrats and pro-choice groups have been worried by a 1985 letter in which Judge Alito - then a 35-year-old official at President Reagan's Justice Department - came out against affirmative action and insisted that the right to an abortion was not protected by the constitution.
Pro-abortion advocates thus fear that, if confirmed, Judge Alito would vote to overturn the benchmark 1973 Roe v Wade ruling that stipulates precisely that.
The second point of contention is bound to be his long history of opinions that, critics say, support strong executive powers at the expense of Congress, the judiciary and the individual.
The topic has become controversial under the "imperial" Bush presidency - especially after the disclosure that the White House used the NSA surveillance agency to conduct wiretapping against US citizens in the US, without warrants.
"Even a state of war is not a blank cheque for the President to do as he wants," the committee's liberal standard-bearer Edward Kennedy told the nominee. He accused him of ruling invariably in favour of government and big corporations, against ordinary citizens.
Senator Kennedy also took him to task over an alleged conflict of interest, when he ruled in 2003 in favour of the Vanguard mutual fund group in which he had money invested.
Judge Alito has dismissed such talk. But he is bound to be questioned on the issue - and his temperament could become a factor. Testy answers could harden Democrats against him, and provoke a filibuster when the nomination goes for final vote in the full Senate.
But with 55 votes, the Republicans are only five short of the 60 required to override an attempted filibuster. The 44 Senate Democrats would have to remain united, while Republicans again threaten to use the "nuclear option" of a rules change to allow a majority to prevail. Democrats could retaliate by bringing the chamber's business to an effective halt.Reuse content