Economy Minister José Luis Machinea resigned from office. He was briefly replaced by the then-Defense Minister Ricardo López Murphy, who himself was forced to resign following negative reception to his shock program. After only two weeks in office, López Murphy was replaced by Domingo Cavallo, who had previously served as Economy Minister between 1991 and 1996, and who was the original author of the Convertibility plan during Menem's presidency. Because of the worsening economic situation and mounting foreign debt, the government enacted two enormous campaigns of debt-expansion and refinancing under the supervision of the International Monetary Fund (IMF), named "The armoring" () and "The Megaexchange" () respectively. From the first moment, there were allegations of corruption and money laundering about the megacanje. The crisis also caused the resignation of all the FrePaSo Cabinet ministers, leaving de la Rúa without political support. The congressional elections of October 2001 were a disaster for the government, which lost many of its seats in the Senate and the Chamber of Deputies to the Peronists. The election results marked also a growing unrest within Argentina's voters, who took to cast millions of null or blank votes. The Peronists seized the opportunity to appoint Senator Ramón Puerta to be President Pro-Tempore of the Argentine Senate, a situation which added to De la Rúa's political weakness since in the Argentine system the President Pro-Tempore of the Senate is next in line for the Presidency after the Vice President. With no Vice President of its own, Puerta's designation meant that De la Rúa had a virtual Peronist Vice President. Social unrest was also growing. Since the late 1990s, protest movements had formed in Argentina, notably the piqueteros ("picketeers"), initially made up of unemployed workers. The piqueteros blockaded major roads and highways demanding government subsidies and other welfare measures. They featured prominently during the March 2001 crisis. The crisis reached a breaking point on 29 November 2001, as major investors began to withdraw their deposits from the banks, summarily causing the collapse of the Argentinian banking system due to capital flight. This was compounded by the IMF's decision to refuse to refinance Argentina's debt. Corralito At the beginning of December 2001, the IMF cut off the flow of funds to Argentina and capital flight became uncontrollable, with 25% of all the money in Argentinian banks having been withdrawn since the beginning of 2001. On 2 December, Finance Minister Cavallo