This paper explores the convergence and subsequent divergence of the socialist and communist movements in Tunisia in aftermath of the First World War, demonstrating the extent to which this moment of uncertainty fostered a diverse range of political views not yet foreclosed by the ascendancy of ethno-centric nationalism. In particular, during the early 1920s, Tunisian leftists cultivated ties with Jewish communities as well as French and Italian settlers, engendering vigorous debates about the prospects of trans-Mediterranean cooperation, the role of the international community in ensuring self-determination, and the radicalism of demands for colonial reform. While the hindsight of Tunisian nationalist historiography has had seemingly little to say about the impact of the First World War on popular political consciousness, recent historical approaches have pushed us to consider the sheer contingency and uncertainty characteristic of the postwar years. Far from a foregone conclusion, Tunisia’s nationalist direction was still in its formative stages in the early 1920s, negotiating and competing in a political field which also included strands of socialism, communism, and even Zionism and pan-Islamic Ottoman revival. Beyond a simple causal chain leading from discrimination and disillusionment at war to anti-colonial nationalist fervor for Tunisia’s tens of thousands of conscripted soldiers and laborers, a close look at the itineraries of postwar political activists paints a more complicated picture. In particular, this paper will compare the trajectories of the “radical” veteran-turned-communist Mukhtar al-‘Ayari and the “moderate” socialist Hassan Guellaty through their writings in the popular Arabic and French press and through police archives, demonstrating the ways in which the Tunisian political field was constructed and contested in the wake of the First World War. These two figures’ transnational encounters crossed and eventually diverged by the mid-1920s, marking the narrowing of Tunisians political horizons which had briefly been blown open by the war. This paper argues that early Tunisian communists’ and socialists’ evolving positions, even in the midst of mounting ethno-nationalist sentiment, reflected both the persistence of trans-Mediterranean cooperation and the insufficiency of terms such as “moderate” or “radical” to explain the diverse political horizons found across the Arab world in the early 1920s.