Washington  - Barack Obama has rarely discussed the issue of race since making history as the first African-American president of the United States.

Yet Obama's pick of Sonia Sotomayor to be the first Hispanic justice on the US Supreme Court has sparked a heated debate about the role of race in US laws, society and business.

The United States' uneasy relationship with race will form the backdrop for Sotomayor's hearing Monday before the US Senate, which has to approve her nomination.

A president's pick for the nine-member Supreme Court, a lifetime appointment, is considered one of his most important decisions. The Senate's deliberations on whether to approve a nomination are often a divisive affair.

Yet some of the usual attacks have been blunted this time around by political considerations: Both parties want to hold on to Hispanic voters, the largest growing demographic in the United States. Sotomayor's nomination is very unlikely to be blocked.

"The Republicans are going to have to be very, very careful on this one," said Melvin Urofsky, professor of law and public policy at Virginia Commonwealth University. "For the Republican Party to be known as anti-woman and anti-Latino will be the kiss of death."

The stakes are also lessened because Sotomayor is unlikely to alter the court's fragile ideological balance. She is considered by most to be a moderate left-leaning judge who will replace the also left-leaning retiring Justice David Souter.

Sotomayor's history has been hailed by Obama as an example of the "American Dream." She is the daughter of Puerto Rican immigrants and grew up in a public housing project in the South Bronx, a poor borough of New York City. Her father died when she was nine years old.

First appointed a federal judge by president George HW Bush in 1992, she was promoted by president Bill Clinton in 1998 to the Second Circuit Court of Appeals in New York. She has also worked as a prosecutor and civil litigator.

Yet it is Sotomayor's ethnicity, and her beliefs about its role in the courts, that has been the biggest source of controversy during the nomination process.

Sotomayor has been unapologetic about the importance that her background and ethnicity play in decision making. She argues that judges should have no illusions over how they are influenced by their own past.

Most controversially, Sotomayor once said she hoped a "wise Latina woman" would make a better decision than a white male. She was referring to discrimination cases, arguing that women and minorities would bring a different set of experiences to the issue.

The remark provoked a sharp backlash from opponents. Newt Gingrich, a former Republican legislative leader, slammed Sotomayor as "racist," though he apologized for the remark a few weeks later.

But Sotomayor's philosophy dovetails with that of Obama, a former professor of constitutional law. Obama has said he wants a judge that shows "empathy" with the lives of people that are brought before the courts.

Sotomayor has "not only a sweeping overview of the American judicial system, but a practical understanding of how the law works in the everyday lives of the American people," Obama said when he nominated her in May.

Opponents believe both Obama and Sotomayor's beliefs smack of "identity politics." For conservatives, impartial justice means that background or race should have absolutely no impact on a judge's decision.

There was "a growing sense, based strictly on the record, that Judge Sotomayor has allowed her personal and political views to cloud her judgment in the courtroom, leading her to favour some groups over others," Mitch McConnell, the top Republican in the Senate, said Thursday.

At the centre of the Senate confirmation hearings will be one key court case that goes to the heart of the role of race and policies like affirmative action in the United States.

The Supreme Court last month ruled against a Connecticut fire department that cancelled a round of promotions because no African- Americans had qualified. The court said the department's decision wrongfully denied the white firefighters advancement.

The Supreme Court's decision overturned an earlier ruling by the New York appeals court of which Sotomayor is a member.

The Republicans' star witness in the hearings will be Frank Ricci, the white firefighter who filed the lawsuit. Frank Vargas, the Hispanic fireman who lost his promotion, will also testify. (dpa)