Courtesy of The Wall Street Journal’s Law Blog here, comes an interview with Marty Lipton, who explains why he invented the poison pill, also called a shareholder rights plan.  There have been several decisions in Delaware over the past few months that have continued a 25-year tradition in which the Delaware courts have upheld the pill (though not in every case). See, e.g., very recent decisions upholding the pill, which were highlighted on this blog here and here.