U.S. Senate Republicans are in a quandary over the Supreme Court nomination of Sonia Sotomayor, aiming to raise pointed questions about her record without angering increasingly influential Hispanic voters.

Senator John Cornyn exemplifies the Republican dilemma over Sotomayor, who is the daughter of Puerto Rican parents who seems certain to be confirmed by the Democratic-led Senate as the first Hispanic Supreme Court justice.

One of seven Republicans on the 19-member Senate Judiciary Committee, Cornyn will take part in what he promises will be tough but civil questioning of Sotomayor, Democratic President Barack Obama's choice, at her hearing starting on July 13.

Cornyn is also chairman of the Senate Republican campaign committee that is charged with expanding a shrinking party and winning seats in the overwhelmingly Democratic Senate.

Hispanics, the fastest-growing U.S. minority who make up 15 percent of the population, are a key to any expansion plans.

Hispanics voted by a two-to-one margin for Obama in last year's presidential election. Many Hispanic voters greeted news of Sotomayor's nomination with joy, and Republicans are aware that Hispanics will be watching carefully how she is handled.