WASHINGTON - Reaching for history, President Obama yesterday chose federal appeals judge Sonia Sotomayor to be the first Hispanic justice on the Supreme Court, championing her as a compassionate, seasoned jurist whose against-the-odds life journey affirms the American dream.

Republicans who will decide whether to make a fight of her confirmation said that they want thorough hearings. Obama, eager to begin putting his imprint on the court, beamed as he introduced Sotomayor as a judge who displays both an impressive mind and heart, a jurist who takes on cases with "an understanding of how the world works and how ordinary people live." He raved about her credentials, saying that she would start on the job with more experience on the bench than any of the current nine justices had when they began.

The White House tableau itself was history: A black president and his white vice president, Joe Biden, striding onto a stage in the ornate East Room with the nominee who grew up in a New York housing project where her parents had moved from Puerto Rico.

At 54, Sotomayor (pronounced SO-TOE-may-OR) would join Ruth Bader Ginsburg as the second woman on the court and just the third in its history. She would replace liberal Justice David Souter, thereby maintaining the court's ideological divide. A number of important cases have been divided by 5-4 majorities, with conservative- and liberal-leaning justices split 4-4 and Justice Anthony Kennedy providing the decisive vote.

Senate Republicans pledged to give her a fair hearing, but cautioned that they would question her rigorously and not be rushed. The president, whose approval ratings trump those of Congress, challenged the Senate to move swiftly.

Democrats hold 59 votes in the Senate, more than enough to confirm Sotomayor but not quite enough to stop a vote-blocking filibuster if Republicans should attempt one.

Born in the South Bronx, Sotomayor lost her father at a young age and watched her mother work two jobs to provide for her and her brother. Her path has soared ever since: Princeton University and Yale Law School, then positions as a commercial litigator, federal district judge and appellate judge.

Said the nominee: "I am an ordinary person who has been blessed with extraordinary opportunities and experiences."

Obama had not met Sotomayor until he interviewed her last Thursday at the White House.

Justices on the nine-member court receive lifetime appointments and can have a profound influence on daily life. Sotomayor would be a new voice on the cases that often reflect divisions in the broader society, including national security, abortion, gay rights and privacy.

As a kid in New York's South Bronx, Sotomayor had to deal with diabetes but dreamed of a career in law, inspired by reading Nancy Drew books and watching "Perry Mason" on TV.

"Although I grew up in very modest and challenging circumstances, I consider my life to be immeasurably rich," said Sotomayor, who smiled broadly as she introduced her mother, Celina, in the front row. The nominee is divorced with no children.

It is her opinions, not her compelling life story, that will shape the tone of her confirmation hearings.

In one of her most memorable rulings as federal district judge, in 1995, Sotomayor ruled with Major League Baseball players over owners in a labor strike that had led to the cancellation of the World Series. "Some say that Judge Sotomayor saved baseball," Obama said.

She became a federal judge for the Southern District of New York in 1992 - nominated by President George H.W. Bush - then an appeals judge in 1998 for the 2nd U.S. Circuit Court of Appeals, which covers New York, Vermont and Connecticut. *