I have my own view on that. The list used to include North Korea, Libya, and Iraq as of three years ago, but as the United States has moved to normalize its relations with these countries.... Great strides were made, for example, with respect to Libya. And after the regime change in Iraq, the point became moot. North Korea I think is the most surprising removal from that list; nevertheless, it occurred.
When a state is removed from that list, it's seen, I think, more as a political overture or attempt to normalize trade and diplomatic relations.