Jaime Rodríguez Calderón, called "El Bronco," is running for governor of Nuevo León in next month's Mexico election. Reuters

A Mexican gubernatorial candidate nicknamed "El Bronco" was gaining support this week ahead of the country's June 7 elections. Jaime Rodríguez Calderón is the first independent candidate to run for governor in Nuevo León, a state with a population of about 5 million, and recent polls indicated he could overtake his opponent in the ruling party, the Wall Street Journal reported.

Mexicans call him "El Bronco" for his determination in bucking the system. “Perhaps he is not going to win, but he is sending a message,” said Eduardo Elizondo, whose brother is a former Nuevo León governor supporting Rodríguez.

Rodríguez, 58, served as mayor of García, Nuevo León, from 2009 to 2012 as part of the Institutional Revolutionary Party (PRI). While in office, he worked to combat drug trafficking in the area -- actions which sparked two assassination attempts on the mayor. He survived and eventually ran to be president of PRI in 2012. He lost by 12 votes to Óscar Herrera and in September 2014 declared himself an independent, according to his website.

Nuevo León usually sees PRI and the National Action Party battle for leadership, but this year is different. Electoral reform measures changed the rules to allow independent candidates like Rodríguez to run, and he's doing well. A recent poll from El Norte showed he, his PRI opponent Ivonne Álvarez and PAN candidate Felipe de Jesus Cantú each had captured about one-third of the popular vote.

Rodríguez's small campaign has been waged mostly on social media, where on Facebook he has more than 474,000 followers. He's run fewer TV ads and raised less money than other candidates. In March, he announced he'd use about 300,000 pesos -- roughly $19,000 -- raised for his campaign to repair potholes in Nuevo León, CNN reported.

Rodríguez has said that the state needs an "efficient, transparent effective and accountable" government that departs from bipartisanship. He wrote on Facebook that he wants to make history in Nuevo León.

"Whatever the outcome, what is happening in Nuevo León reveals the disillusionment of society with an exhausted and discredited political system," El Pais columnist Jorge Zepeda Patterson wrote Friday. "An eventual victory of this candidate could lead to a high-risk management, in effect, but the electoral life would never be the same in this country. Not a bad balance."