He returned to Chacabuco in 1994 and was elected Mayor the following year on the ruling Justicialist Party ticket. Domínguez was elected to the Lower House of Congress in 1999, but forfeited his seat following an offer for the post of provincial Public Works Minister by Ruckauf, who had been elected Governor of Buenos Aires. He was influential in the governor's 2001 decision to rescind the province's water service concession granted several years earlier to Azurix, a local Enron subsidiary. The precipitous resignation of President Fernando de la Rúa at the end of 2001 and his eventual replacement by a leading Peronist figure, Eduardo Duhalde, brought Domínguez to the Casa Rosada as the President's Assistant Chief of Staff. He served mainly in a parliamentary liaison capacity in this post, and the election of Néstor Kirchner to the Presidency in 2003 took Domínguez to an important Defense Ministry post, where he served as liaison between the Argentine Military and the remaining, civilian arms of the Argentine Government. He was elected to the Buenos Aires Province Legislature in 2003, and his work with Ruckauf and Duhalde, both former governors who still wielded influence in the provincial capital, helped result in Domínguez's prompt election as the body's Justicialist Party caucus Whip. He became prominent in the Judiciary Committee, becoming its Chairman and the Vice President of the Lower House itself following his reelection in 2007.
Minister of Agriculture and later work
Fallout from the 2008 Argentine government conflict with the agricultural sector over a proposed rise in export tariffs led to a number of changes in the executive branch, including the creation that year of a Production Ministry and, on September 30, 2009, the reinstatement of the Agriculture Secretariat as a ministry, a prominence the post had not enjoyed since 1981. Supported by Presidential Chief of Staff Aníbal Fernández, Domínguez was tapped for the post and sworn in on October 1. Pending, however, were improvements in strained relations between the center-left administration of President Cristina Kirchner and nation's important agrarian sector, whose leading figures approved of her decision to reinstate the Agriculture Ministry, but expressed skepticism at the appointment to the post of a legislator with no farming experience, and who had recently supported a hike in provincial farm income taxes. Domínguez's tenure saw the federal government regain the initiative to some extent vis-à-vis the agrarian sector. The contentious entity regulating agricultural subsidies, ONCCA, was dissolved in 2011; and the proposed return to a Federal Grain Board, as well as the revival of the Federal Agrarian Council of provincial officials dealing with the sector, succeeded in dividing the powerful agrarian lobby round table, the Mesa de Enlace. Elected to the Argentine Chamber of Deputies in 2011, he was named president of the body on December 6.
