I doubt it will be as unexpected as, “is this because I’m a lesbian?,” but tonight we might find out how Thompson’s character gets written off Law & Order.

…Lewin was in turn replaced (defeated for re-election, presumably, although the show never made that explicit) by District Attorney Arthur Branch, a conservative Republican played by Fred D. Thompson, the former Tennessee senator. In May, Mr. Thompson asked NBC to release him from his “Law & Order” commitments as he prepared to explore a presidential run. The network announced that it would stop showing reruns of the episodes he appears in because of federal regulations requiring equal television time for presidential candidates. How Branch will be written off the show will, presumably, be disclosed in tonight’s episode.