Control of cases

An American attorney licensed in each applicable court may in a few cases control and argue his or her case at each level of the judiciary through its entire lifecycle. A notable example of this is the Brown v. Board of Education litigation, where the same trial team handled the case from start to finish at the U.S. Supreme Court. However, cases which advance to the appellate level, particularly to the U.S. Supreme Court, are often re-assigned to experienced appellate practitioners or firms.

Source: http://en.wikipedia.org/wiki/Attorney