Well, a lot, when talking about a major newspaper reporting for years about a United States Supreme Court Justice and regularly misspelling her name since 1980. Apparently, the New York Times issued a retraction on October 28, 2008 following an article about an award to be given to Justice Steven Breyer by Fordham University Law School. The article mentions, in passing, Justice Ruth Bader Ginsburg by name. The retraction reads:

Correction: October 30, 2008
An article in some editions on Wednesday about Fordham University’s plan to give an ethics prize to Supreme Court Justice Stephen G. Breyer misspelled the surname of another Supreme Court justice who received the award in 2001. She is Ruth Bader Ginsburg, not Ginsberg. The Times has misspelled her name at least two dozen times since 1980; this is the first correction the paper has published.

What is to be learned? Double check the spelling of your proper names if you are going to put them in print. Or hire new editors.