The Outer Limits - Season 2 Episode 9 Trial by Fire

On the day of Charles Halsey's inauguration as President of the United States, scientists detect a large object heading towards Earth at half the speed of light. Halsey, a peace-loving liberal, is rushed to an underground bunker by the Presidential transition team, a group of aides and military men that share the hawkish bent of the previous administration. As the crisis unfolds, it becomes clear that the object came from an armada of alien ships, which are fast approaching Earth. Contact is made, but the aliens' message is unclear. As the U.S. and the other nuclear powers gear up to defend themselves, Halsey must decide: Are these invaders bent on conquering earth or benevolent explorers reaching out to another civilization?