These points emerged during testimony by Lt. Col. Oliver L. North yesterday.

ON TAKING THE RAP North said he was part of a Reagan administration plan, drafted in part by the then-CIA Director William J. Casey, to be the "scapegoat" and shield the president and other high officials from repercussions of the Iran-contra operation. He was prepared to take the blame "for whoever necessary."

But on Nov. 25, when Attorney General Edwin Meese III announced that a criminal investigation had begun, North said he changed his mind about remaining silent. He said his "mind set changed considerably" when he realized that a criminal prosecution was at stake since he was "prepared to take the rap for political purposes, but not for criminal purposes."

ON FOLLOWING ORDERS North repeatedly testified that all of his actions while an aide at the National Security Council were authorized by his superiors, suggesting that he did not break the law because he was merely following the orders he considered legal.

ON PRESIDENTIAL APPROVAL Until the last weekend he worked at the White House, North said he believed that President Reagan knew and approved his support of the contras, including the diversion of profits from arms sales to Iran to maintain the Nicaraguan rebels.

ON LAST-MINUTE SHREDDING Even as investigators from the attorney general's office examined documents in his office last November, North was shredding documents just a few feet away. The Justice Department investigators saw what North was doing, he said, but did not ask him to stop.

ON HIS ATTORNEY North's attorney, Brendan V. Sullivan Jr., declaring he was "not a potted plant" during one of several exchanges with the committee and its counsel, has been a combative, tenacious advocate for his client. Lawyers say Sullivan is trying to protect North from possible perjury charges by reducing the number of times he is forced to answer the same question and is deflecting attention from North to give him time to formulate answers.