[cnn-photo-caption image= http://i.l.cnn.net/cnn/2008/POLITICS/02/12/potomac.primaries/art.mccain.va.ap.jpg caption=" Sen. John McCain picked up wins in Virginia, Maryland and the District of Columbia on Tuesday."]WASHINGTON (CNN) - While Sen. John McCain was inching toward the Republican presidential nomination, Sen. Barack Obama staked a claim as the Democratic front-runner.
Obama's wins in the District of Columbia, Maryland and Virginia primaries propelled him past Sen. Hillary Clinton in the race for delegates.
According to CNN calculations, Obama has 1,215 delegates to Clinton's 1,190.