Mayor of Dasmariñas

Barzaga was elected Municipal Mayor of Dasmariñas in 1998 and served in that office for nine years.^{[citation needed]} In 2007, he defeated incumbent representative Gilbert Remulla for the House of Representatives seat for the Second District of Cavite.^{[citation needed]} His wife Jennifer succeeded Barzaga as mayor of Dasmariñas.^{[citation needed]}

Congressman

In the House of Representatives, Barzaga serves as vice chairman of the Committee on Constitutional Amendments, Local Government, and Revision of Laws and is a member of the Committees on Appropriations, Civil Service and Professional Regulation, Good Government, Human Rights, Justice, Population and Family Relations, Public Works and Highways, Science and Technology, Suffrage and Electoral Reforms, Transportation, Veteran Affairs and Welfare and the Special Committee on Southern Tagalog Development.^[1]

He figured prominently on issues concerning Meralco, Sulpicio Lines, the Impeachment Complaint, and Alabang Boys. He has authored and sponsored several bills including an act converting Dasmariñas into a component city,^[2] a resolution requesting an investigation into oil prices, a resolution requesting an investigation into bidding on updating the Subic Bay Freeport Zone master development plan, and a resolution requesting an investigation of environmental issues during the construction of a casino in Subic Bay Freeport Zone.

In 2009, along with fellow representatives from Cavite Joseph Emilio Abaya and Jesus Crispin Remulla, Barzaga co-authored a congressional reapportionment law that increased the representatives of Cavite from three to seven.^[3]

In the 2010 elections, he won a landslide victory against his opponent Ramon Campos of the Nacionalista Party.

Serving as part of the House Prosecution panel, Barzaga was responsible for Article II of the 2012 impeachment of Chief Justice Renato Corona. He was paired against his remedial law professor, former Associate Justice Serafin Cuevas, who was the lead defense counsel.^[4]

In 2013 elections, he sought reelection for his last term under the National Unity Party. He was also nominated by the Liberal Party.

In 2015, he was criticized by the National Union of Journalists of the Philippines for threatening to cite journalist Christine F. Herrera of The Standard in contempt, after the latter refused to disclose her sources regarding the alleged bribes provided to lawmakers to expedite the passage of the Bangsamoro Basic Law. Barzaga was one of the solons who voted "Yes" for the passage of bill at the committee level.

He supported the candidacy of Mar Roxas in the 2016 Philippine elections.^{[citation needed]} Barzaga predicted that Grace Poe will not run as the running mate of Roxas, and instead will run under the Nationalist Peoples Coalition, with the idea of a Roxas-Aquino tandem to challenge the Grace-Chiz tandem.^[5] Barzaga declined to run for Governor against Remulla, and instead ran for mayor of Dasmariñas.

Denial of the renewal of ABS-CBN franchise

In 2020, Barzaga was prominently featured in the hearings for the renewal of ABS-CBN's congressional franchise when he cited Wikipedia as his source of information.^[6] He was one of the 70 representatives who voted to deny the franchise renewal, in favor of the report from Technical Working Group.^[7]