President Barack Obama awarded a posthumous Medal of Honor, the highest US award for bravery, on Tuesday to a Jewish soldier and a black soldier, for gallantry during World War One, cases that were dogged by concerns over discrimination.Obama awarded the medals to Sergeant William Shemin of Bayonne, New Jersey, and Private Henry Johnson, of Albany, New York, 97 years after they saved comrades on French battlefields."They both risked their own lives to save the lives of others," Obama said in the White House ceremony. "It's never too late to say 'thank you.'"Shemin, a Jewish soldier who served with the 47th Infantry Regiment, 4th Infantry Division, repeatedly exposed himself to heavy fire to rescue the wounded from Aug. 7 to 9, 1918.After officers and other non-commissioned officers had become casualties, Shemin took command of his platoon until he was wounded on Aug. 9.Two of Shemin's daughters, Elsie Shemin-Roth of Webster Grove, Missouri, and Ina Bass, accepted the Medal of Honor on behalf of their father.Johnson, a member of the all-black 369th Infantry Regiment, known as the "Harlem Hellfighters," and Private Needham Roberts fought off an attack by a raiding party of at least a dozen Germans while on night sentry duty on May 15, 1918.Despite being wounded and under heavy fire, Johnson forced the Germans to retreat and kept Roberts, who was badly wounded, from being taken prisoner, Obama said.The Army's website for Johnson said he advanced armed only with a knife and killed a German by stabbing him through the head.Command Sergeant Major Louis Wilson of the New York National Guard accepted the medal on Johnson's behalf.Worries about racism have tinged the delay in awarding the medals to Johnson and Shemin. France awarded Johnson and Roberts the Croix de Guerre with palm for their actions, but Johnson went unrecognized by the United States.Obama said Johnson was denied a Purple Heart medal despite being wounded 21 times and was so disabled he could not go back to his pre-war job as a railway porter. Johnson died in 1929.Shemin received the Distinguished Service Cross, one step below the Medal of Honor, but little explanation was offered for why the higher award for which he was nominated was not approved.After Army service, Shemin ran a landscaping business in New York and had three children. He died in 1973.