Simplify the following text for a Grade 12 native English-speaking person.
Original: John Marshall ( September 24 , 1755 â `` July 6 , 1835 ) was the Chief Justice of the United States ( 1801-1835 ) whose court opinions helped lay the basis for American constitutional law while promoting nationalism and making the Supreme Court of the United States a center of power with the capability of overruling Congress .
Simplified: John Marshall ( September 24 , 1755 â `` July 6 , 1835 ) was an American statesman and jurist who shaped American constitutional law and made the Supreme Court more powerful .