Paul Krugman: If we discovered that space aliens were planning to attack and we needed a massive buildup to counter the space alien threat and really inflation and budget deficits took secondary place to that, this slump would be over in 18 months. And then if we discovered, oops, we made a mistake, there aren't any aliens, we'd be better –Yup. The solution to the problem is space aliens. He's not the only "expert" to resort to space aliens. Francis Crick, Nobel Prize winner and co-discoverer of the DNA double-helix, found it impossible for the complexity of DNA to have evolved naturally. So, he proposed a theory that Earth was originally seeded by space aliens.....the fancy term for it being "directed panspermia."
Ken Rogoff: And we need Orson Welles, is what you're saying.
Paul Krugman: No, there was a Twilight Zone episode like this in which scientists fake an alien threat in order to achieve world peace. Well, this time...we need it in order to get some fiscal stimulus.
Just because someone has some award or is considered an "expert" doesn't mean that they don't ever come up with stuff that's totally off the wall nuts. A lot of times there is very good reason to question what the "experts" are saying.