NEW YORK (Reuters) - The Republican National Committee asked the charity of Democratic nominee Hillary Clinton’s family on Monday to produce all correspondence its staff had with the U.S. State Department while Clinton served as America’s most senior diplomat.  Clinton’s campaign to win the Nov. 8 presidential election has been dogged by criticism that donors to the Clinton Foundation may have expected special favors from the U.S. government in return. She says donors to the global charity receive no preferential treatment.     “The Clinton Foundation can play a vital role in filling important gaps in the public record by demonstrating its commitment to transparency and making public all correspondence its officials had with the State Department during Secretary Clinton’s tenure,” Reince Priebus, the RNC chairman, said in a letter to the foundation’s president, Donna Shalala.  The RNC provided a copy of the letter to reporters.      Spokesmen for Clinton and the foundation, which is known for its work to widen access to HIV medicines in developing countries, did not respond to a request for comment. Some emails have already emerged that show Clinton Foundation officials seeking meetings with Clinton and other diplomats on behalf of supporters who have made large donations to the foundation.  Foundation officials also sought other favors, including help with visa issues or urging the government to hire certain people, emails show. Spokesmen for Clinton have noted that in several cases the requests from foundation officials were unsuccessful. Thousands more emails from Clinton’s tenure are still in the process of being released as public records. Their release was delayed in part because of Clinton’s decision to use an unauthorized private email server for her work without informing record-keeping officials.  In his letter, Priebus said the foundation’s own records have “the unique ability” to establish whether donors received special treatment.     Clinton promised President Barack Obama that her family’s charities would annually disclose all their donors and seek prior approval from the State Department for any additional money given by foreign governments when Obama made her his most senior diplomat in 2009. The charities said last year they failed to comply with the promises, blaming oversights. The foundation has said it will no longer accept foreign or corporate funding for at least some of its work if Clinton is elected. Her daughter, Chelsea Clinton, will remain on the board. 