PORTLAND — Oregon and a few other states will lead workshops this year to train Mexican prosecutors as that country changes its court trial system from closed, document-only affairs in a judge’s office to a more open system similar to the one in the United States.

In most Mexican states, “It’s all done on paper, in written form,” said Cecilia Maciel-Lopez, a former judge and chief prosecutor for the border city of Mexicali and the surrounding area.

Oregon and the other states will do the training funded by the U.S. Agency for International Development and coordinated by the Conference of Western Attorneys General and the National Association of Attorneys General.

Karen White, executive director of the Conference of Western Attorneys General, said U.S. prosecutors have received $1.5 million from USAID to train up to 600 Mexican prosecutors over three years.

She said Oregon was chosen because of its expertise in tracking and prosecuting online sexual predators. “Oregon’s attorney general’s office excels at that,” she said.

She said the sessions are being held at the request of the prosecutors. The Oregon session will be this spring, she said.

A constitutional amendment approved by Mexico’s 32 states and signed by President Felipe Calderon last summer gives that country until 2016 to change over.

Defendants would be presumed innocent until proven guilty. There is no presumption of innocence in many Latin American countries, a holdover from the old Napoleanic Code.

By opening the courtroom, reformers hope to reduce chances for corruption and increase the public’s confidence through transparency.

“Keep in mind that some of the things we think of as a universal truth are not universal truths in the rest of the world,” said Jose R. Juarez, dean of the Sturm College of Law at the University of Denver. “They are breaking away from what is really a well established tradition.”

Maciel-Lopez said she hopes trials wouldn’t last the years they can take now, with files often lost under piles of papers on a judge’s desk.

To Jorge Aranda, a prosecutor from the Gulf of California seaside community of San Felipe, the oral adversarial system seems to mimic what Mexican authorities do now on paper.

“We know the law,” Aranda said. “But now, we’re going to present the law with a little bit of drama. We can do that.”

By November, Maciel-Lopez said, her office hopes to be working in a new courthouse with public galleries. She plans to have rest of her staff of 200 trained by then.

Reforms have been implemented in the Mexican states of Nuevo Leon, Chihuahua and Oaxaca, with the next states to switch being Baja California Norte, Morelos and Zacatecas, said Jorge Gonzalez Mayagoitia of the Mexican consulate in Denver. Reforms will be implemented separately in the federal court system.

Other workshops will be held this year in Texas, Idaho, Washington, and Colorado.