Obama seeks to sell accord

Speech coincides with anniversary of US-Soviet test ban treaty, which is seen as a benchmark

US President Barack Obama is casting a looming congressional vote on the Iran nuclear deal as the United States' most consequential foreign policy debate since the authorization of the Iraq War, a now unpopular decision that still reverberates through US politics.

In a bid to discredit criticism of the deal, Obama also will argue in a speech on Wednesday, Washington time, at American University that the people who supported the Iraq War now oppose the diplomatic deal with Iran.