No deal on Iran 'will lead to war'

Obama tells Congress to stand firm on vote or Washington will lose its international credibility

US President Barack Obama made an aggressive case for his signature nuclear deal with Iran on Wednesday, telling lawmakers that rejecting diplomacy would lead to war and destroy US credibility.

Casting it as "the most consequential foreign policy debate" since the Iraq War, Obama said Congress must not waver under pressure from critics whom history had already proven wrong.