Top stories this week are likely to include: the Mexican presidential election pushes forward after last night’s debate; Chávez to file presidential candidacy today; Fernández de Kirchner to visit UN on Thursday; new UNASUR Secretary-General takes over; Brazil responds to lowered GDP projections; and B-20 business summit in Los Cabos.

Mexican Presidential Election: After last night’s second and final debate between the top four contenders for the Mexican presidency, the final weeks of the campaign are likely to see continued discussion over the candidates’ positions on how to fight nacrotrafficking and insecurity. Each candidate sought to spell out how their approach would differ from President Felipe Calderón’s heavy reliance on the military. According to the New York Times, the candidates, “while vowing to continue to fight drug trafficking, say they intend to eventually withdraw the Mexican Army from the fight,” pledge “to devote more attention to programs that address the social inequality that leads young people to join criminal groups.” In polling, PRI candidate Enrique Peña Nieto continues to hold a steady lead while PRD challenger Andrés Manuel López Obrador (AMLO) has moved into second. On AMLO, AQ Editor-in-Chief Christopher Sabatini notes that “despite his recent rise in polls, credible surveys still put him a very distant second and well outside the margin of error.”

Chávez to File Today: Venezuelan President Hugo Chávez will register his presidential candidacy in person today for re-election to a third term in the October 7 contest. Henrique Capriles Radonski, opposition challenger, filed his candidacy yesterday after a 6.2-mile (10 kilometer) march through Caracas flocked with tens of thousands of supporters. Chávez’ debilitating health after nearly a year of cancer treatment raises a constant red-flag. Notes Sabatini, “Capriles Radonski’s march through the city was intended to be a demonstration of strength, a counterpoint to Chávez’ absence and the mystery of his health. But will it work? Many of the old wedge issues remain, irrespective of perceptions of Chávez’ health: What will happen in a post-Chávez scenario both in terms of political turmoil and the still-popular misiones?”

Brazil Reacts to Lower GDP Projections: Economic forecasters have lowered Brazil’s projected 2012 GDP growth from 2.72 percent to 2.53 percent, according to Reuters. The revised figures are due to problems in the manufacturing sector and the European debt crisis, according to a poll from Brazil’s central bank. “While Europe and a slowing in Chinese demand are adversely affecting Brazilian manufacturing, the long-term challenge is to reduce the ‘Brazil cost’ of excessive bureaucracy, inadequate infrastructure and other manufacturing hurdles that companies face,”  according to AQ Senior Editor Jason Marczak.

CFK at the UN on Thursday: Argentine President Cristina Fernández de Kirchner (CFK) will attend the UN Special Committee on Decolonization meeting, known as the Committee of 24, this Thursday. According to Argentine Cabinet Chief Juan Manuel Abal Medina, CFK “expects a strong definition in terms of advancing in the path of dialogue and reaching an agreement to recover our Malvinas Islands.”

New UNASUR Secretary-General: Today, the Union of South American Nations (UNASUR) secretariat shifts from Colombia to Venezuela. All chancellors of UNASUR countries are currently in Bogotá for a ministerial-level meeting at the Casa de Nariño, where María Emma Mejía, former Colombian foreign minister and current UNASUR secretary-general, will hand over the secretariat to Venezuelan businessman Alí Rodríguez Araque, who was formerly the Organization of Petroleum Exporting Countries (OPEC) secretary-general and president of Petróleos de Venezuela S.A. (PDVSA), Venezuela’s state-owned oil company.

B-20 Summit to Precede G-20: The B-20 business summit will convene on Sunday and Monday in Los Cabos, Mexico, as an antecedent to the G-20 next week. The B-20’s objective, according to its website, is to promote dialogue between governmental and business leaders, enrich the discussions of the G-20 and facilitate the G-20’s objectives such as economic growth and social development. A sample of working groups in this year’s B-20 will include food security, green growth, employment, anti-corruption, and trade and investment.