DUBAI, United Arab Emirates — Two months after the implementation of last year’s landmark nuclear agreement, a US diplomat is on an unlikely mission — promoting the Iran deal to firms that want to tap into its massive market but fear other sanctions or that the next American president could scrap the deal.

It’s not an easy task for Chris Backemeyer or other Americans on the equivalent of a nuclear deal roadshow, especially as Iran’s Revolutionary Guard continues to fire off ballistic missiles and US Republican presidential candidates vow to tear up the pact.

Despite the political risks in both countries, Backemeyer said the deal to lift sanctions in exchange for limiting Iran’s ability to enrich uranium will prevent the country from being able to build a nuclear weapon and is likely to survive the contentious debate of the campaign season.

‘‘Throughout our history, there’s been a lot of arms-control agreements and nuclear agreements that have been violently opposed by whatever party was not in the office at the time, and most of them have lived with them afterwards,’’ said Backemeyer, the State Department’s principal deputy coordinator for sanctions policy.

While EU firms have charged ahead into Iran, US firms or those with US interests have moved much more cautiously. That’s due to a number of US sanctions still in place, such as ones over Iran’s ballistic missile tests.

In order to ease the concerns of business, Backemeyer and other State Department officials have met with companies in Dubai and elsewhere.

Associated Press