The U.S.A. leadership, especially presidents, for 2 centuries have been propelled by irrational HATRED. 
Early leadership hated Native Americans so much they wiped them out in a century of wars, even genocide. 
Then the South's economic success became too much for the North, who suddenly developed hatred of black slavery to justify a war to wipe them out. Lincoln after all was from way North. 
Somehow American leadership developed a deep hatred of Hitler before WW2, even though Nazi Germany have not done a darn thing to hurt America. 
After WW2, unable to wipe out the other winning country the USSR, American leadership suddenly developed insane hatred of Communism, but which they loved during WW2. 
GW Bush is all about hatred of all things Islamic. He tried to wipe it out with war. 
Obama, a black man, suddenly found a resurgent Russia who challenged his Exceptionalism. He tried to war on it, but got defeated. 
And now we have The Donald. He hates China very much. Very very much.