John Poindexter, President Reagan's national security adviser, asked a federal appeals panel to overturn his convictions and six-month prison sentence in the Iran-Contra scandal.

Poindexter, a retired Navy rear admiral convicted of five felony counts in the worst scandal of Reagan's administration, sat in the front row of the courtroom Thursday during an unusually long hearing by a special three-judge panel.Poindexter was convicted of lying to Congress about the Iran-Contra scandal, but his lawyers argued it was not illegal to intentionally mislead Congress. They said Poindexter had merely engaged in a "political dialogue" while attempting to deflect congressional investigations.

Poindexter was engaged in "political dialogue" and "political advocacy" when he briefed Congress about aspects of the scandal, Poindexter's lawyer said.