As a teacher, writer, editor, and activist, Idár preserved Mexican culture in South Texas and encouraged women to pursue an education and push for equal rights. While working as a journalist, she became the president of the newly-established League of Mexican Women — La Liga Femenil Mexicanista — in October 1911, an organization with a focus on the education of Mexican children, in Laredo to offer free education to Mexican children. In 1914, when she returned from her volunteer nursing work at the border, she began writing for El Progreso. An editorial published in El Progreso that criticized President Woodrow Wilson’s order to dispatch U.S military troops to the Mexico-U.S. border had offended the Texas Rangers. The Rangers attempted to close El Progreso, but Idar blocked the entrance to the newspaper's office. When she was not at the newspaper's office one day, the Rangers returned to ransack it and to destroy the printing-presses, effectively shutting down the newspaper.