Four summit-level visits (two in each direction) in a single year is something incredibly unique. Normally, one would expect that this would yield a strategic condominium, or at least a LOT more measurable cooperation, but that hardly seems to be the case. That is partly because on the Venn diagram between what Beijing wants and what Washington wants out of this relationship, the overlapping middle has shrunk quite a lot from when I got into this business decades ago. So there really just isn't the growth of tangible, measurable government-enabled cooperation that you would expect from such a frenetic pace of summits. Form and function are diverging rather dramatically, compared to the decade of the 2000s, which I would describe as the high water mark of regional and global coordination between the United States and China. I wrote on that in this long essay for @TheNatlInterest when Trump was elected in 2016: