The Mexican governors had written that they would not step foot in Arizona because they considered the law, which Ms. Brewer signed in April and continues to promote, to be “based on ethnic and cultural prejudice contrary to fundamental rights.”  Their position is in line with that of President Felipe Calderón of Mexico, who has denounced the law on several occasions as a recipe for singling out Mexican citizens, lawfully in the United States or not, for harassment. It also coincides with a boycott announced by major civil rights groups in the United States and several cities and towns.  Now, Gov. Bill Richardson of New Mexico has stepped into the fray, pledging to salvage the conference by finding a site in another state.  “Governor Brewer doesn’t have the authority to cancel the Border Governors Conference,” Gilbert Gallegos, a spokesman for Mr. Richardson said. “She may not want to host it for political reasons, but that’s not a reason to sidestep the tough issues that border governors must address, including migration and border violence. Governor Richardson will look for alternative sites to host the conference, with or without Arizona’s participation.”  Mr. Richardson, a Democrat and the nation’s only Hispanic governor, had lobbied Ms. Brewer, a Republican, not to sign the law, and he has repeatedly condemned it.  A spokesman for Gov. Arnold Schwarzenegger of California, who took particular pride in hosting the conference in 2008, said he also supported moving it.  It remained unclear if Ms. Brewer would attend the conference if it ended up in another state.  A call to Margie Emmerman, Ms. Brewer’s adviser on border affairs and coordinator of the conference, was referred to the governor’s press office, which did not respond to a call or an e-mail message on the subject.  Polls in the United States may show that a majority of Americans support the Arizona law, or at least the concept of a state’s playing a greater role in immigration enforcement, but abroad the law is strongly opposed and has raised concerns at the State Department that it could strain diplomatic relations with Latin America.  On a recent tour in South America, Secretary of State Hillary Rodham Clinton was peppered with questions about it at every stop, and she took the unusual step of disclosing that the Justice Department intended to legally challenge it even before government lawyers finished preparing the case.  For now, the conference Web site, hosted by the State of Arizona, shows no sign of the conflict. In fact, Ms. Brewer has a statement on it declaring, “I am excited to host this year’s event.”  She adds: “We will continue to promote mutual prosperity for the states along the U.S.-Mexico border region, as we foster stronger relations between our two countries. The Border Governors Conference is the premier forum for analysis, dialogue and support for specific initiatives and policies that address the unique needs of our border region.”  The forums resemble any international summit, and raise similar questions over what tangible results come of them. A couple of years ago Mr. Schwarzenegger, serving as host in Los Angeles, took a delegation of governors on a fact-finding trip to the Universal Studios theme park.  But aides to the American governors say the conferences have produced concrete results, including agreements to share intelligence on gun trafficking, exchange information on the H1N1 virus and lobby the governors’ respective federal governments to improve border crossing infrastructure and procedures and commerce.  There has been tension in the past, including a couple of years ago when all four American governors declared a state of emergency at the border over illegal immigration and drug trafficking. Similarly, when Mr. Schwarzenegger urged in 2005 that the border be closed, his attendance at that year’s conference in Torreón, Mexico, rankled Mexicans.  But aides to the governors said they could not recall any previous conference being canceled.  A version of this article appears in print on July 7, 2010, on Page A1 of the New York edition with the headline: Law in Arizona Is Causing Split In Border Talks. Order Reprints| Today's Paper|Subscribe
For nearly three decades, governors from both sides of the United States-Mexico border have held a conference, but this year, things are uncertain.