The U.S. Congress lost the longest-serving member in its history on Monday when West Virginia Senator Robert Byrd passed away at 92. Who will replace him? It appears that, according to West Virginia law, Governor Joe Manchin III, a Democrat, will be able to select a replacement to serve out the remainder of Byrd’s term until 2012. However, there’s reasonable grounds for a challenge here: The law states that if a vacancy occurs more than two-and-a-half years before the term is up, a special election may be held; Byrd died two years, six months, and five days before his term expires. But the law also holds that the special election will not take place until after a candidate “has been nominated at the primary election next following such timely filing and has thereafter been elected”—the “next” primary not being scheduled until 2012. Still, it’s reasonable to expect a legal challenge to force a special election sooner; had Byrd died just one week later, all of this would be moot since the legal ambiguity would be eliminated. West Virginia has little experience in these matters, as Byrd has held his seat since 1959 and West Virginia’s other senator, John D. Rockefeller, since 1984.