This summer is the harvest season for Obama's diplomacy. First, the reconciliation and resumption of diplomatic relations with the enemy, Cuba, have resolved the thorniest problem half a century since the U.S. diplomacy surrounding the United States. Further, they have pushed for a comprehensive agreement on Iran's nuclear issue and become an example of diplomatic efforts to solve complex international hot issues.
 
　　Of course, the follow-up to the above-mentioned two diplomatic events will not be easy. Conservative members of the United States are likely to obstruct the appointment of ambassador to Cuba. They may also create obstacles for the United States to legally accept the agreement on the Iranian nuclear issue. In any case, these two things are enough to be the most dazzling achievement of the Obama administration in the field of diplomacy.
 
　　Both Cuba and Iran have a long history of dating back decades and the U.S. presidents hope they will both make efforts to solve both these problems. Why the final qualitative change occurred during Obama's tenure? There are three main reasons.
 
　 　First, the comparative changes in the strength of the international pattern have brought a sense of urgency to the parties in resolving the issue. The United States is increasingly aware that it is hard to maintain its global leadership position and instead uses more cleverness to attach importance to the legitimacy of its actions and international charisma and seek multilateralism. However, Cuba and Iran, which have abundant resources, have been slowing their economic development primarily because of foreign policy. It should be said that times are changing and parties are more aware of what they really want.
 
　 　Second, the pragmatic diplomatic line of the Obama administration. Just as Obama took office as president, what he took from Bush was a severely damaged U.S. diplomacy. Obama understands that his predecessor's hard-line style, the priority of being forced by armed forces to make the U.S. diplomacy passive and the excessive use of force have weakened the U.S. global image and leadership. Therefore, the key words of its first domestic foreign policy can be described as "withdrawing" from the withdrawal of troops from Iraq and Afghanistan and making a modest strategic contraction. The second key word for any internal-foreign policy should be "talking", priority should be given to negotiations and no immediate military intervention should be avoided, especially if the ground forces are to be fought. This is evident on Syria. Although criticized as weak, it has resulted in the settlement of two issues, Cuba and Iran.
 
　　Third, the personal factors of Obama. Obama originated from grass-roots, twists and turns of his childhood life had a subtle influence on his later character, he cautious, but not decisive, slightly less execution. Coupled with his political career unlike his predecessor, Bush, Clinton, Bush, etc. served as governor or federal government officials, but served as a lawyer and senator, lack of administrative experience. This would have been his weakness, but to a certain extent he has also become his advantage: such as attaching importance to listening, tolerating disagreements and acting steadily. In foreign policy, he refuses to use force more and instead emphasizes the importance attached to the negotiation.
 
　　In addition, one of the most pressing realities is that in the face of Republican-controlled House of Representatives, Obama realizes that it is hard to do anything in the internal affairs and instead looks for a breakthrough in the diplomatic field in order to leave behind a political legacy.
 
　　In short, a slap beat. Rouhani, Castro is also facing internal pressure, after all, the people's eating is the most real need, their ideas coincide with Obama, shaking hands and words are reasonable.
 
　　In resolving the establishment of diplomatic relations with Cuba and the issue of Iran's nuclear agreement, Obama has received powerful external help. It seems that the solution to both problems stems from time and place. I do not know whether this will have any bearing on the current U.S. counterparts left behind by "opposing" North Korea or even Russia's leaders. After all, the present Obama seems to be the "best-spoken" leader in U.S. history.