Hi all. I read this in an article appeared in Economist: "it is a stretch to belive that Wells can be effective to monitoring foreign institutions." I guess here "it is a stretch to believe" roughly means "It is hard to believe" . But I feel "it's a stretch to believe" and "it's hard to believe" differs in the emphasis and intensity they implies. Am I right? What does "it is a stretch to believe" exactly mean ? Is it a common expression is English language? Thank you.