An expert on the history of the Holocaust this week challenged the selection of the president of West Germany as Commencement speaker saying the European statesman has systematically lied in defense of his father who was a chief diplomat for Nazi Germany.

In an article published in two area newspapers, Francis L. Loewenheim--a professor at Rice University--charged that while this year's Commencement speaker, Richard von Weiszacker, is an eloquent voice of the need for modern Germany to bear responsibility for Nazi war crimes, he has distorted his father's own role in those atrocities.

Loewenheim, the author of several books on Germany, said von Weizsacker assisted his father, Baron Ernst von Weizsacker, in authoring untruthful memoirs of the Baron's war years. The historian also said that the president--who served as his father's lawyer during the Nuremberg trials--claims to this day that his father was unaware of the existence of death camps in the face of what Loewenheim called overwhelming evidence to the contrary.

The elder von Weiszacker was charged by the international tribunal with assisting in the deportation of Jews to Nazi death camps and served 18 months in prison.

"To misrepresent the past is a very serious matter and morally reprehensible," said Loewenheim in an interview yesterday.

"A man so conspicuously lacking in candor and truthfulness...has no business gracing--or disgracing--Harvard University's 1987 Commencement as its principle speaker," the historian wrote yesterday in an opinion piece published in the the Boston Globe.

Harvard officials yesterday defended the choice of von Weiszacker, whose selection as the speaker for the 336th Commencement was announced in March.

The president of West Germany has been hailed by various Jewish groups--such as B'nai Brith's Anti-Defamation League and the World Jewish Congress--as a "unique" voice in modern Germany, because of his call to fellow Germans that they bear the responsibilities that derive from thecountry's Nazi past.

Von Weizsacker has been specially praised for a1985 speech he delivered on the 40th anniversaryof Germany's unconditional surrender. Many saidthe speech was an eloquent response to the moralproblems raised in Germany and the United Stateswhen President Reagan visited a Bitburg cemeterythat contained the graves of members of theS.S.--the Nazi elite guard.

"His courageous and magnificent speech standsas one of the great political and moral statementsof recent European history," Geyser UniversityProfessor Henry Rosovsky said at the time of theannouncement.

In an interview yesterday, Rosovsky, who isJewish, said Loewenheim's attack was "mostunfair." Rosovsky is a member of the HarvardCorporation that chooses the Commencement speaker.He said that it was wrong to hold the sonaccountable for the actions of his father.

"Perhaps, he has a blind spot about hisfather's [actions]," the former Dean of theFaculty said. But he added, "for a son to attemptto defend his father is an understandable act."Rosovsky also pointed out that von Weizsackerreceived an honorary degree from Tel AvivUniversity and had recently made a state visit toIsrael.

Rabbi Ben-Zion Gold of Harvard Hillel said hethought von Weiszacker was an excellent choice asCommencement speaker. He also attacked those whowere critical of the West German president. "It isparticularly disturbing because people have becomeguilt peddlers," Gold said.

Other members of the University said they weredisappointed in the choice of von Weiszacker.Professor of Law Alan Dershowitz said the Germanpresident was "a man who, more than most admitshis own guilt, yet denies his father'santi-Jewish, anti-Catholic past."

"He sees this honorary degree as a means ofvindicating his family name. I don't think Harvardshould be part of his vindicating his familyname," Dershowitz said.