Negotiator is a heavy missile truck with unmatched range within T2 mobile units. It shoots missiles along a high-altitude arc enabling you to take down targets covered by walls and hilltops. Its awesome range make it a perfect siege weapon, able to quickly obliterate enemy’s defensive structures and destroy strategic targets like geothermal powerplants etc.
It is very costly but its huge damage output makes it worth a shot.
Helpless against mobile units, always keep it protected by your infantry. A bit cheaper than its ARMADA counterpart, the Ambassador.