They tried, Pan-Arabism was popular in the 50s with Nasser and his UAR with Syria. The Americans were worried that Pan-Arab Republic would be Soviet-aligned though so they provided significant support to Islamist parties like the Muslim Brotherhood to divide the Arab world

following the 1952 military revolution in Egypt and rise to power of the charismatic President Gamal Abdel Nasser, U.S. officials began to fear an Egyptian rapprochement with the Soviet Union. This led the U.S. to reconsider the Muslim Brotherhood, which came to be described in official cables not as fanatics, but as “orthodox believers.”

Subsequently, regular meetings were held at the U.S. Embassy in Cairo between the American Chargé d’affaires Frank Gaffney and the General Guide of the Muslim Brotherhood, Hassan al-Hudaybi. By the mid-1950s, when relations between the Ikhwan and Egypt’s military rulers collapsed after an initial period of cooperation, the U.S.’s engagement with the Brotherhood came to be seen increasingly by American diplomats as a possible opportunity to pressure the Soviet-aligned military government in Cairo.

The US also provoked Gadaffi overthrow for the same reason: worried about socialist influence and threat of Arab unity. So they had him brutally executed by islamist rebels. Similar situation in Afghanistan with Osama bin ladin and the socialist government there, though that one came with some serious blowback. These are just a few examples, I urge you to research more about American imperialism in the Middle East, because the United States has played a very major role in the region since the end of the second world war.