From RAND:

The main difference between the immediate post-Cold War decade and the post-9/11 era as regards the variety of international challenges is that during that earlier period these challenges were faced and dealt with seriatim, rather than allowed to accumulate. Each of the above cited hurdles was taken, for the most part successfully, before the next was encountered. As a consequence, the George H.W. Bush and Clinton administrations usually had the luxury of managing only one serious crisis at a time.