In the May 1947 crises (or exclusion crises), the Communists were excluded from government in Italy and France. The crises are commonly reckoned to be the start of the Cold War in Western Europe.
In Italy, the Christian Democrats (DC), led by Alcide De Gasperi, were losing popularity, and feared that the leftist coalition would take power. The Communist Party of Italy (PCI) was growing particularly fast due to its organizing efforts supporting sharecroppers in Sicily, Tuscany and Umbria, movements which were also bolstered by the reforms of Fausto Gullo, the Communist minister of agriculture. On 1 May, the nation was thrown into crisis by the murder of eleven leftist peasants (including four children) at an International Workers' Day parade in Palermo by Salvatore Giuliano and his gang. In the political chaos which ensued, the president engineered the expulsion of all left-wing ministers from the cabinet on 31 May. The PCI would not have a national position in government again for twenty years. De Gasperi did this under pressure from US Secretary of State George Marshall, who'd informed him that anti-communism was a pre-condition for receiving American aid, and Ambassador James C. Dunn who had directly asked de Gasperi to dissolve the parliament and remove the PCI.
In France, conflicting policies of members of the governing Tripartisme coalition created tensions, and economic conditions were dire under the presidency of Paul Ramadier. The French Communist Party (PCF) had the support of one in every four voters, polling the largest percentage of votes of any party between 1946 and 1956. Ramadier received warnings from the US Ambassador Jefferson Caffery that the presence of Communists in the government would lead to the blocking of American aid, or perhaps worse. ("I told Ramadier," Caffery wrote in his diary, "no Communists in gov. or else.") Ramadier began looking for a pretext to purge them. As the great French strikewave of 1947 began, a rumor circulated among the ministers in Ramadier's party, the SFIO, that the Communists were plotting a coup for 1 May, and the military was secretly mobilized. The Communist ministers opposed Ramadier in a vote on wages policies, and, on 5 May 1947, he expelled them from the government. The following year, the US rewarded France with hundreds of millions of dollars in Marshall Plan aid. No evidence of coup plot was ever found, and it was confirmed that the PCF had initially opposed the April strikes. The Communist Party's absence from government in France lasted well beyond the fall of the Fourth Republic, and the effect of this absence upon the party system and the stability of government have prompted historians such as Maynard Williams to describe 5 May 1947 as 'the most important date in the history of the Fourth Republic'.
The Italian political crisis and anti-communist movement were dependent on Mafia violence. The Mafia made deep connections with the Christian Democrats in the mid-1940s through figures such as Calogero Vizzini, who was also an operative for the US military. The politicized Mafia employed terror as a tactic against the labor movement and the Communist Party, killing dozens of leftists in this period. The 1 May massacre by Salvatore Giuliano is often alleged to be one of these Christian Democrat-associated events. According to Peter Robb, "The mafia had commissioned the crime for the politicians...just as it was picking off individual communists, socialists, and trade unionists. Another dozen had been killed that same year of 1947...The mafia was making itself useful to its new political protectors by dispatching its enemies, a pattern that was to continue for decades." Prior to his mysterious killing in state custody, Guiliano lieutenant Gaspare Pisciotta implicated the DC directly for the massacre through Ministry of the Interior Mario Scelba. Writers such as Gaia Servadio and Peter Dale Scott believe there was US involvement through an intelligence-mafia network run by William J. Donovan. While specific accusations are controversial, there is consensus that Giuliano "was being used as a vanguard in a domestic political battle with the Communists." 
Communist ministers were dismissed from several other European governments in 1947 and in all cases the move was dictated by a desire to comply with the wishes of the United States. These maneuvers led the Soviets to harden their approach to foreign policy, establishing the Cominform.