How do you she wrote it at BHO's request, or that BHO was involved with it in any way?
Good question, but you're jumping the gun. You're assuming that's it's accurate to say to begin with that Sarah Herlihy is Obama's friend. And there's no evidence to support any such relationship.
I don't pretend to be an expert on these matters, but there is a connection, second-hand:
A partner at the Chicago law firm of Kirkland and Ellis, Bruce Ettelson, was on the finance committee for Obama back in 2006.
Another partner at the same firm, Jack Levin, received an award from Obama at a Chicago event during the relevant period of time.
Sarah Herlihy, a junior member of the same law firm and at the time only ONE year out of law school, writes an article about the natural born requirement of the Constitution.
In her article, the opening paragraph leaves no doubts about her position: "The natural born citizen requirement in Article II of the United States Constitution has been called the 'stupidest provision' in the Constitution, 'undecidedly un-American,' 'blatantly discriminatory,' and the 'Constitution’s worst provision.' ”
And the most intriguing, and subtle, evidence is the article's total omission of BHO.
Sure, if he wasn't natural born, and the senior attorney knew it, there would be no reason to mention BHO alongside the other foreign-born politicans in the USA -- Schwarzenegger, Granholm, etc. But if the evidence was clear regarding BHO's birth, then mentioning BHO would have amplified Ms. Herlihy's point greatly, something like, "the country is fortunate that the natural birth requirement isn't even more restrictive, otherwise young and brilliant politicians like our own Barack Obama, whose father was a native Kenyan, would be inelgible for office."
The total omission of BHO from the article is what makes this doubly intriguing.
I'd say there's enough of a connection to take note. If you were an attorney friend of BHO (you might be a lurker at FR for all I know), it'd be awfully easy for you to direct a junior member of the law firm to do such an article.