The children of presidents have long captured the imagination of Americans - and criticism. A television anchor said Chelsea Clinton had been "pimped out" by her parents. A radio talker called Amy Carter ugly. Susan Ford had her dates critiqued. Children of presidents back to Lincoln and beyond have been rhetorical targets - almost exclusively girls and young women in recent decades. Now, the biting criticism of Sasha and Malia Obama by a Republican congressional aide has struck a new chord, particularly among African-Americans who hold up the first family as an icon of black family success. "The symbolic nature of this president and this first family in many black households outweighs the substance of the presidency itself," said James Peterson, the director of Africana studies at Lehigh University. "I'm a substance guy, but the symbolic nature of this president is a force to be reckoned with." Elizabeth Lauten, the communications director for Republican Congressman Stephen Fincher reportedly resigned on Monday after receiving a torrent of criticism in social media for a post on her Facebook page that caustically criticised the Obamas' teenage daughters the previous week during the annual pardoning of a Thanksgiving turkey at the White House. "Try showing a little class," Lauten wrote on Facebook. "Act like being in the White House matters to you. Dress like you deserve respect, not a spot at a bar." Lauten apologised later on Facebook. "I reacted to an article and quickly judged the two young ladies in a way that I would never have wanted to be judged as a teenager," wrote Lauten. But the damage had been done. "Black folks might not be gung-ho for Team Obama these days, but the Obama girls are untouchable," said Mark Anthony Neal, a professor of African and African-American studies at Duke University. "When she [Lauten] discussed them lacking class, that not only struck a chord with blacks but with non-blacks, because the Obamas are viewed as role models for families." Republican aides on Capitol Hill agreed that Lauten broke one of the cardinal rules of politics. In the words of one senior aide: "You're always free to invoke your own children, but invoking other people's kids is not among the things you should do." Instead, Republicans objected to what some called the overwrought media attention to the comments of a low-level aide of a rank-and-file congressman. Some Republican officials suggested that the media attention helped a bid by Democrats to exploit the kerfuffle for political gain. "Children, especially the first daughters, are off limits. While the comments were inappropriate and insensitive, the mainstream media's coverage of this story is appalling," Republican National Committee communications director Sean Spicer wrote in a series of messages on his Twitter account. "In over 20 years in politics I have never seen one of the countless inappropriate comments by Democrats ever covered" to this extent. Though criticising presidential children - especially young ones - is considered out of bounds, the practice is almost as old as the democracy itself. In 1966, Lyndon Johnson's then-18-year-old daughter complained that "we don't get paid, but we sure get criticised". In a Newsweek interview, she noted that when her grades "weren't so good, complete strangers scolded me. And they got better and we sort of leaked the news about my B average - people said I was bragging." Susan Ford was criticised for wearing blue jeans in the White House and had her high school dates critiqued. "I kept thinking, 'I want to be normal. But I can't be normal,' " Ford, then Susan Ford Bales, told the San Francisco Chronicle . "Everyone was watching." Former first daughter Patti Davis wrote an open letter to Sasha and Malia, noting that she was criticised for an outfit she wore to an event with Queen Elizabeth when her father, Ronald Reagan, was president. "There were 150 people there. 149 of them were properly dressed," she said the journalist wrote. "As first daughters, you can't win," Davis wrote to the girls last week. "There will always be bitchy people sitting at their keyboards, seething with anger at their own lives, ready to take it out on you." As teenagers, first daughters Amy Carter and Chelsea Clinton came under particularly vociferous criticism, with Rush Limbaugh at one point calling Carter the "most unattractive presidential daughter in the history of the country". He eventually apologised, but later, holding up a photograph of then-13-year-old Chelsea Clinton on his 1993 television show, he asked his viewers, "Did you know there is also a White House dog?" Clinton has since said she developed a thick skin as a way to deflect attacks. "I have the dubious honour of being compared to a dog as a 13-year-old by Rush Limbaugh," she said earlier this year, addressing the National Conference for College Women Student Leaders at the University of Maryland. "That was not about me, that was about him." Chelsea Clinton was a target again after her family left the White House, when then-MSNBC correspondent David Shuster suggested she was being used as a political prop by her mother's 2008 presidential campaign and asked whether she was being "pimped out". He was suspended by the network. President George W. Bush's twin daughters, Jenna and Barbara, were criticised for under-age drinking and for sticking out their tongues at photographers. Historian Doug Wead, a staffer in the George H.W. Bush White House who wrote about what he called the "triumph and tragedy" of first families in the book All the Presidents' Children , says the critiques of first families stretch back into earlier eras. Robert Todd Lincoln was criticised for avoiding service in the civil war while Franklin Roosevelt's children were accused of receiving preferential treatment in the military. "The idea that children aren't involved, that it's taboo, is incorrect, but in recent times we've all been very respectful," Wead said. Theodore Roosevelt's eldest daughter, Alice, who moved into the White House when she was 17, was a constant source of consternation for observers, Wead said. "The pulpits of America were filled with sermons every weekend about Alice Roosevelt," Wead said, noting that her smoking was considered scandalous. She also drove a car, without a chaperone: a drive from Washington to New York "was followed in the newspapers as if it were Lindbergh crossing the Atlantic", he said. At one point, Roosevelt said to an exasperated visitor, "I can run the country and I can be a father to Alice Roosevelt, but I can't do both." Additional reporting by The Washington Post