Ok I caught that his time is 10th best all-time, which would clearly put him in the top 10. However using the half-marathon as a race to rank this performance as best ever by an American isn't valid.
If all the best 10k runners were to race every year in a half-marathon I would reasonably expect all of the top 20 would break 1:00:00 in a flat course in perfect weather.
What I can't wait to see is Hall in the 10,000 this year. The AR is now very intriguine with Ritz and Hall as leading contenders. Meb seems to be totally focused on the marathon. Also don't forget Tegenkamp if he decides to give this a shot.
I wonder which direction Hall will go now. He ran back to back 10ks plus a 1200 in 28:20 pace. Sub 27:20 for him seems to be where he's at in a 10,000 right now. But 30:00 pace for a marathon, 18 seconds slower per mile, and he's at 2:06 for the marathon. There is no marathoner right now in America who I think is capable of that at the moment.
America has certainly come a long way in the distances these last few years from the bad era of the early-mid 1990's. Hall just ran back to back 28:20's and I recall some years when 28:20 would have been a top 5 yearly performance for an Amwerican nationally in the 10,000.