SAN ANTONIO — Texas Sen. John Cornyn headed up a Congressional hearing on the North American Free Trade Agreement in San Antonio on Monday.

"I do know the failure to renegotiate and modernize NAFTA would be very bad for Texas and the United States," said Cornyn.

The agreement was signed 25 years ago, and its supporters said it is essential for the U.S. economy.

"Trade generally, NAFTA specifically, means jobs. For Texas more than 380,000 jobs that depend on Mexico alone," said Paola Avila with the Border Trade Alliance.

"If you just look at the question of plant openings, since NAFTA there have been 26 that have come online since NAFTA, 14 in the U.S., 11 in Mexico, 1 in Canada," said Mitch Bainwol with the Alliance of Automobile Manufacturers.

But even NAFTA's supporters say the agreement needs some fixes. Labor activists are concerned it slights workers.

"The main thing we're interested in the new NAFTA, the renegotiation process right now, is that workers don't get forgotten," said Bob Cash with Texas Fair Trade Coalition. "The old NAFTA was a great success for the economic elites for the one percent in Mexico, Canada, and the U.S." 

"If a worker gets paid one hour for a month what they get paid here in the U.S., that's unacceptable," said Montserrat Garibay with Texas AFL-CIO.

Cornyn also thinks NAFTA needs some tweaking, but President Trump has talked about withdrawing from it completely. Cornyn said that would be a mistake.

"I hope that any talk of withdrawal is maybe just a negotiating technique or rhetoric and it's not real because I do believe it needs to be modernized," Cornyn said.

Senator Cornyn said the country has seen huge changes since NAFTA was first signed, in particular, the rise in digital commerce. He thinks that will be a huge focus of the agreement's modernization.