Writing about first kids is a tricky business that at best will get you scolded online and at worst send you to the unemployment line, as former Hill staffer Elizabeth Lauten found out recently. But if there is a gray area when it comes to first offspring (as children, they’re so off-limits, but what about when they grow up and get Instagram accounts?) Lauten’s social media screed and resulting resignation underscores the message that the first kids remain third rails.

After posting a Facebook missive that criticized Malia and Sasha Obama for their seemingly so-over-it demeanor during the White House turkey pardon last week, Lauten, the former communications director for Rep. Stephen Lee Fincher (R-Tenn.), first apologized and later resigned amid mounting criticism.

“Try showing a little class,” Lauten wrote in her original Facebook post. “Rise to the occasion. Act like being in the White House matters to you. Dress like you deserve respect, not a spot at a bar.”

Call it an unspoken code of professional conduct or just plain ol’ common sense, but if there is one rule of engagement for covering (or practicing) politics, it’s this: leave the kids out of it.

For starters, Lauten was a Capitol Hill staffer, a class of folks who know that their every move and word can reflect on the boss. “Most people in most offices understand that as a staffer, your words are not your own,” says Rebecca Gale, who pens a Capitol Hill workplace-advice column for Roll Call newspaper. So in the weird world of online rants, the words of a “GOP staffer” sting harder than, say, those of a dental hygenist’s or insurance agent’s.

Press secretaries — the people tasked with protecting lawmaker’s public images —  should be more aware than most about the possibility that whatever they post on social media networks can spread far beyond their circle of “friends,” she notes. “That’s the basis of your job.”

And for someone with a platform (Lauten’s Twitter handle is “DCGOPgirl” and she has a healthy 14,000-plus following), picking on teenagers’ appearances goes against the generally accepted code. “If she had criticized the president’s policies, or even his clothes, no one would have batted an eye,” Gale says.  Even a more measured comment about their clothes would have been unlikely to provoke a firestorm, Gale says.  “But everyone knows you leave kids out of the mudslinging.”