Complex sentence: Even in the cases where the soldier wanted to marry the mother of his child, he was prevented by the US Army, which prohibited any interracial marriages until 1948, when the Army was integrated by Executive Order of President Harry Truman.
Split into simpler sentences: Even in the cases where the soldier wanted to marry the mother of his child, he was prevented by the US Army. It prohibited interracial marriages until 1948, when the Army was integrated by Executive Order of President Harry Truman.