The union between the two countries came out of desire of pan-Arabism and fear of communist insurgence in Syria. Afif al-Bizri, chief of staff for the Syrian army was a communist sympathizer, which was of concern for many in the region, which some politicians in Iraq, Jordan, and Lebanon considering supporting an intervention to overthrow the Syrian government. In addition, the Syrian Communist Party under party leader and MP Khalid Bakdash was growing in strength. During this political crisis, the Ba’ath Party of Syria turned to Egypt for aid in peaceful resolution. Egyptian president Gamal Abdel Nasser, concerned of a communist takeover in Syria, agreed to proposals to a union between the two countries. Nasser’s terms for a union heavily favored his own policies, requesting “a plebiscite, the dissolution of parties, and the withdrawal of the army from politics.”. While many Syrians were concerned about these extremists demands, they eventually supported the merger, fearing communist growth to be more harmful to Syrian politics.

There was an obvious preference for Egyptian concerns over Syrian ones in the union. Under Nasser’s rules for the new national assembly, there were 400 Egyptian members, but only 200 Syrians. Mustafa al-Barudi, Syrian Minister of Propaganda, described the feeling many in his country felt getting the short end of the stick:

“…the smallest member of the (Egyptian) retinue thought that he had inherited our country. [Egyptians] spread “like octopuses” everywhere.”

Reaction to the union in other parts of the Middle East was as well controversial, with Jordan and Iraq forming their own union to rival (it lasted a mere six months). In Lebanon, the issues of wherever they should remain tied to the west or joined the Egypt-Syria union was so intense it led to a three-month political crisis with at least 1300 dead.

In 1961 a military coup in Syria threaten the status of the union. The new leaders were frustrated with Nasser’s nationalized economic policies and Egypt’s increased control over Syrian life, but offered to stay in the union if their demands were met. Egypt refused, with Nasser considering sending troops to preserve the union, this failed to pass after the last of his allies had been removed. The UAR was no more, the efforts to curb Arab communism and enforce pan-Arabism in Syria had resulted in Syrians losing basic principles of their political system, such as the existence of political parties, to Egyptian influence. Dissatisfaction to Nasser’s Syria policy had resulted in the Syrians concluding it was better to rule independently from now on.

Sources:

Aburish, Said K. (2004), Nasser, the Last Arab, New York: St. Martin's Press

Encyclopedia Britannica "United Arab Republic (U.A.R.)".

Jankowski, James P. (2002), Nasser's Egypt, Arab Nationalism, and the United Arab Republic

Palmer, Monte (1966), The United Arab Republic: An Assessment of Its Failure, 20 (1), Middle East Journal

Podeh, Elie (1999), The Decline of Arab Unity: The Rise And Fall of the United Arab Republic, Sussex Academic Press

Stephens, Robert (1971), Nasser: A Political Biography, New York: Simon and Schuster

Tsourapas, Gerasimos (2016). "Nasser's Educators and Agitators across al-Watan al-'Arabi: Tracing the Foreign Policy Importance of Egyptian Regional Migration, 1952-1967". British Journal of Middle Eastern Studies. 43 (3): 324–341.