One may mistakenly assume that Arab Baathism and the Arab Socialism espoused by Nasser were the same, but this is categorically untrue. As a matter of fact, while the first successful revolution and state-building apparatus was established by Nasserism, Baathists emerged later than 1952 and only seized power in Iraq in 1968 and in Syria in 1963, and the Baathist governments were immensly hostile to Nasserists within their countries.
Nasserism differs from Baathism in terms of its party-driven policies, while Nasserism espouses indiviual leadership, Baathist ideology, which originated with Michel Aflaq and Salah al-Din al-Bitar in Syria, instead focused with a party-driven approach, which is somewhat similar to the Bolshevik policies in terms of a "vanguard party" and how the party secures the revolution.
Due to the party-oriented approach of the Baathists, regional rivalries were common and to be expected. They were united in opposition to socialists from Egypt and those who espoused their ideas but later turned on each other, with the party in Iraq separating from the party in Syria.
Nasser, as all men do, would eventually die, and Anwar Sadat distanced Egypt from the socialist and pan-Arab policies of Nasserism. Meanwhile, the dictatorships in Iraq and Syria remained in full force until the modern era. However, they too would eventually fall—the Baath Party in Iraq was forcibly dissolved after the 2003 invasion, and the Syrian party was dissolved after the fall of Damascus in December 2024.
Nasser would later distance himself from the Baathist parties. However, before he died, he delivered a scathing rebuttal against them in 1962, stating that the Baath Party had segregated Syrians into Baathists and non-Baathists, and that leadership positions were given based solely on party membership. He also accused the party of exacerbating social and religious tensions for its own benefit. Considering that the Baath Party had been warned of its downfall as early as 1962, this was likely not just Nasser’s personal view but his objective analysis of the situation.
To be specific, he accused the party of "fascism" and stated that it had "divided the country into Baathists and non-Baathists." He also accused the Baath Party of engaging in sectarianism and relying on minorities through false promises.
While the fall of the Baath parties has occurred, it will take years to conduct an objective analysis of their legacy—although it is unlikely to be favorable toward them.