the president took a jab at the wisconsin governor during an interview with npr morning edition host steve inskeep .
obama was responding to walker 's claims that he 'd ` absolutely ' cancel or ` disown ' a deal with iran on ` day one ' if elected to higher office .
jab at walker departed from the white house 's general strategy of staying out of the race to replace the sitting president .
walker fired back on twitter : ` americans would be better served by a president who spent more time working with governors & congress rather than attacking them '
obama defended the informal agreement his administration made with iran and the shift toward cuba , which it may take of its list of terrorist countries .