President Reagan has plunged again into the Iran-Contra scandal's legal quagmire by declaring his belief in the innocence of former White House aides Oliver North and John Poindexter.

Some legal experts said the president's remarks on Monday, the latest of several comments in support of his former aides, could prejudice the trial and make jury selection difficult.But U.S. District Judge Gerhard Gesell has ruled that the widespread publicity should not prejudice the case in which the two aides are charged with fraud in diverting funds to the U.S.-backed Nicaraguan Contra rebels.

Reagan, responding to a reporter's question on Monday, said, "I believe in the innocence of the two men, and I would like to see that established once and for all."

The president caused a furor earlier this year by declaring he did not believe North had committed any crime. He did not mention North and Poindexter by name in the Monday comment, but an official confirmed the president was referring to them.