An editorial discussed Iran’s “determined program to attain nuclear-weapons capacity.” Later, it cited pressure on Iran “to halt its aggressive program to attain a nuclear bomb.”
What Iran is trying to do is “attain” nuclear capacity so it can “obtain” a nuclear bomb.
“Attain” and “obtain” both have the sense of “getting” something. But “attain” has embedded in it the sense of a goal that is reached through some effort; “obtain” carries more a sense of “procuring.”
Garner’s Modern American Usage calls both “attain” and “obtain” “formal words,” used in “an elevated level of diction.” Garner’s calls the mixup a malapropism, or a misuse with a humorous result, like saying “she was under the affluence of her sugar daddy” instead of “influence.”
Most misuses of “attain” or “obtain” are not funny, simply because they are “wrong” only to a matter of degree. If you spent years and hundreds of dollars before you finally got that Derek Jeter rookie baseball card, you might say, “When I finally obtained that Jeter card, I attained the status of the greatest baseball-card collector.” You obtained a physical thing, and thus attained a milestone or goal.
Few people will misunderstand if you misuse either one. But if you’re going to play at an “elevated level of diction,” you should at least try to fit in.