Washington: President Barack Obama launched a 60-day campaign to sell the historic nuclear deal with Iran to lawmakers and the nation at large, challenging its Republican critics to present a better alternative.

Taking his case to the media, he asserted at an hour-long news conference at the White House Wednesday that the deal would prevent Iran from making nuclear weapons and claiming that the alternative is military force.

‘Either the issue of Iran obtaining a nuclear weapon is resolved diplomatically, through a negotiation, or it’s resolved through force, through war,’ he said. ‘Those are the options.’

‘If the alternative is that we should bring Iran to heel through military force, then those critics should say so. And that will be an honest debate,’ Obama said asking the Republicans and its global critics like Israel to present an alternative.

‘It is incumbent on the critics of this deal to explain how an American president is in a worse position — 12, 13, 14, 15 years from now — if, in fact, at that point, Iran says, ‘We’re going to back out of the (deal), kick out inspectors, and go for a nuclear bomb,’’ he said.

Claiming that the chief goal in the marathon negotiations between six world powers led by the US and Iran was to ensure Tehran cannot make a nuclear bomb, Obama said: ‘This deal is our best means of ensuring Iran does not get a nuclear weapon.’

Obama also hit back against critics who said that international inspectors would not have instant access to nuclear sites anywhere in the country, saying the deal established thorough monitoring ‘24-7’.

‘This is not something you hide in a closet. This is not something you put on a dolly and wheel off somewhere,’ Obama said of enriched uranium and plutonium.

Republicans from members of Congress to 2016 presidential hopefuls have slammed the deal as caving to Iran.

Israeli Prime Minister Benjamin Netanyahu, who enjoys bipartisan support in Washington, has called it a ‘historic mistake.’

The Republican-controlled Congress has sixty days to review the agreement and has the option of passing a resolution of disapproval.

But Obama has vowed to ‘veto any legislation that prevents the successful implementation of this deal.’

It would take two thirds majorities in both the House and the Senate to override the presidential veto.

The President said that while some members of Congress — including some of his own Democratic Party — have legitimate concerns, others are simply playing anti-Obama politics.

‘I am not betting on the Republican Party rallying behind this agreement,’ he said.

Obama Wednesday sent Vice President Joe Biden to meet with members of the House Democratic Caucus some of whom have also expressed reservations about the deal.