Washington ? Republicans are divided over how aggressively to go after Sonia Sotomayor, a family feud about the tone of the debate over confirming the first Hispanic on the Supreme Court.

There are concerns raised by an increasing number of GOP lawmakers and conservative leaders about the strident rhetoric that certain prominent Republicans have used to describe Sotomayor. Some are denouncing right-wing groups for their negative advertisements against the federal appeals judge.

A group of prominent conservatives, seeking to change the terms of the discussion, plans to call on Republicans this coming week to hold “a great debate” over President Barack Obama’s nominee. The debate would focus on Sotomayor’s potential effect on important high court decisions and on the differences between how Democrats and Republicans pick judges.

In a letter to be sent to GOP senators Monday, the Third Branch Conference admonishes Republicans for having “slumbered” during confirmation hearings for the last two Democratic nominees (Ruth Bader Ginsburg and Stephen Breyer, both by President Bill Clinton), and concludes by saying, “We expect more from you” this time.

The Associated Press obtained a draft of the letter, signed by conservative heavyweights including Richard Viguerie of ConservativeHQ.com, David Keene of the American Conservative Union, and Gary Bauer of American Values.

The letter acknowledges that blocking a vote to confirm Sotomayor is unrealistic. But it urges Republicans to use the debate as an “extraordinary educable moment” that makes it “crystal clear why Americans should believe that Republicans are intelligent defenders of the Constitution, or not.”

Manuel Miranda, the chairman of the group and a former senior Senate aide, said he is concerned that GOP leaders, knowing they lack the votes to reject Sotomayor and worried about the political consequences of a prolonged opposition, will pass up the chance for a drawn-out debate about her record, and the parties’ dueling philosophies on a judge’s role.

Radio host Rush Limbaugh and former House Speaker Newt Gingrich have branded Sotomayor — the daughter of Puerto Rican parents who was born and raised in New York — a “racist” for past remarks about how her ethnicity affected her judging. On Friday, Limbaugh said picking Sotomayor was comparable to nominating former Ku Klux Klan leader David Duke for the job.

Other leading Republicans, aware of the political risks of opposing the first Hispanic woman nominated to the court, are struggling to change the terms of the debate. Sen. John Cornyn, R-Texas, the head of his party’s Senate campaign committee, lashed out at Limbaugh and Gingrich for their words.

“This is not the kind of tone that any of us want to set when it comes to performing our constitutional responsibilities of advise and consent,” Cornyn told National Public Radio.

Writing in the Wall Street Journal, GOP strategist Peggy Noonan dismissed as “idiots” those conservatives who were out to attack or brand Sotomayor.