Hikaru the Champion
Hikaru Nakamura represents the best chance for the United States to one day regain the World Chess Championship. Can he do it? He didn't even qualify for the candidates match in 2013. In truth, I think was a good thing. As we observed in the Anand/Carlsen match, mental state, more than just preparation, can play a significant role in the overall result.
While the candidates tournament was going on, and we were missing Nakamuru (and Caruana, who is also a US citizen, but plays for Italy) from the field. As the two best players not participating, they certainly were feeling sore about it. However, I think Hikaru missing the candidates will in the end be a good thing. The drive to win is one thing, but the drive to prove yourself over others can be even greater. In many sports with drafts, such as the NFL, being drafted in the later rounds, or later than expected, is considered to be a good thing, because you are going to work harder to prove the teams who passed on you wrong. I think Hikaru has this chance now.
Recent coverage has indicated that Hikaru seems to be in this head space. Peter Doggers interview on this site (http://www.chess.com/news/hikaru-nakamura-i-feel-good-im-optimistic-1927) leads me to believe that Hikaru is maturing, but not losing his drive for greatness. Skipping the US championship to participate in the Gashimov Memorial may seem like a no-brainer, but it's an important step. Hikaru recently mentioned not wanting to play in lesser tournaments and concentrate on only playing the best in the world, and this is an example of that.
If Hikaru can achieve the appropriate mental state, there is nothing in chess that can stop him. His losses to Magnus have been more psychological than tactical or positional. Hikaru expects to lose to Magnus, and then it happens. We'll seen at the Gashimov if he can break through and beat the champ. If so, everything will change.