That's the most important part of that guy's statement, really. A person with as much access to the relevant intelligence data as literally anyone on the planet (and with a history of loyal support of this administration, so little if any chance of political motivation to lie) explicitly stated that this was not an "imminent threat."

If the threat is not legitimately imminent, I'd argue that a war that's causing bloodshed, ruining decades-long alliances, costing billions daily, and engendering massive negative ramifications to the global economy is not in fact (immediately) "necessary."

Among other dubious rationales, this was an attempt at producing a "rally 'round the flag" effect for this administration, and it's failed miserably at that.