Are all barriers on trade intentional?

Nations protect domestic certain industries by so many ways. Increasing tariffs is an main effectively
process from other countries. Protective tariff not only can reduce the amount of imports entering a country, also increase sales for domestic producers. On the other hand, nations like to use increasing
tariffs to solve the antidumping problems.

Indeed, there were some barriers on trade  were unintentionally. For example, war on terror is an terribly
negative unintentionally barriers on trade. The famous war on terror was 9.11 event ten years ago. 9.11
event created particular adverse effect to America economy. First of all, investors lost their trust for
America economy market. They thought America was not a safe place to invested anymore. In addition, the United States utilized a large number of domestic resources to the war against terrorism after 9.11 event. Then, Military expenditures and national debt of America has increased rapidly. The war on terror makes a heavy blow to America's economy.

In China, the war on terror occurred in the north western province of Xinjiang. The terrorists those who are fighting for an independent state was uighur separatists.  Uighur separatists keep separatism many years because they believe they are different between us. Uighur take different language and culture that make them special, but it's not means they are not Chinese. Uighur fought people who are not uighur, and vicious burned shops during the war on terror. This negative event created very bad impact for China economy. From ancient times till now, the only thing war on terror can gave us was painful.
Hope the war on terror won't happen again in anywhere.