WASHINGTON (Reuters) - Some Republican Party backers of abortion rights are upset with their party's new chairman, Ken Mehlman, for planning to host a salute next week to those who favor banning abortion. "This crosses the line," Ann Stone, national chair of Republicans for Choice, a political action group with about 100,000 members nationwide, said on Friday. Mehlman has scheduled an event on Monday to honor those who participate in the march that day against the 1973 U.S. Supreme Court decision that legalized abortion. our party's fight to protect the sanctity of life."