 Seaborg enjoyed a close relationship with President Lyndon Johnson and influenced the administration to pursue the Nuclear Non @-@ Proliferation Treaty . Seaborg was called to the White House in the first week of the Nixon Administration in January 1969 to advise President Richard Nixon on his first diplomatic crisis involving the Soviets and nuclear testing . He clashed with Nixon presidential adviser John Ehrlichman over the treatment of a Jewish scientist , Zalman Shapiro , whom the Nixon administration suspected of leaking nuclear secrets to Israel . 
