María Adelina Isabel Emilia "Nina" Otero-Warren (October 23, 1881 – January 3, 1965) was an American woman's suffragist, educator, and politician.

On October 23, 1881, María Adelina Isabel Emilia (Nina) Otero was born on her family's hacienda “La Constancia,” close to Los Lunas, New Mexico.

[1] Her ancestors' successful "sheep drives" in California in the Gold Rush era enabled the family to develop political connections and rise to being landowners.

[1][3] In 1883, her father died during a quarrel against a band of Anglos who questioned his property ownership, leaving his daughter fatherless at the age of two.

[1] Her mother raised Adelina within the traditional realm of a Spanish Hacienda in Los Lunas, surrounded by relatives and other well-to-do Hispanic families.

[2] From 1892 to 1894, Otero-Warren attended a private Catholic boarding school (later known as Maryville College of the Sacred Heart) in Saint Louis, Missouri.

This school helped develop her social consciousness, and it imparted the idea that women could have careers as teachers and community leaders.

"[2][3] After returning from her time in St. Louis, she taught her siblings what she had learned in school, and asked her male relatives to teach her how to shoot pistols and other firearms so she could protect herself.

While she lived in the city, she was active in Anne Morgan's settlement house, an organization aimed to aid working-class women.

[2] Among many some of Otero-Warren's closest friends were artists and writers who impacted the 20th century's progressive movement, including Mary Austin, Witter Byner, Mamie Meadors, and Alice Henderson.

[citation needed] Otero-Warren also made close ties with Ella St. Clair Thompson, the woman who headed the Congressional Union for Women's Suffrage upon her arrival in New Mexico.

[3] Her commitment to working with women's groups and lobbying legislators for suffrage helped her rise in the leadership ranks in the state Congressional Union (CU).

"[3] Otero-Warren also sought support for suffrage though her other political leadership roles as the chair of legislative committees for the Republican Party and the New Mexico Federation of Women's Clubs.

Otero-Warren lobbied New Mexico congressmen to vote in favor of the Nineteenth Amendment, and she was so influential because of her uncle and other Hispanic relatives who were elected leaders.

She played such an important role in this activist effort that Alice Paul, the leader of the CU, credited Otero-Warren with ensuring New Mexico ratified the Nineteenth Amendment.

Controversy abounded, however, when news of her divorce came out during her election, as well as concerns about her stance on Spanish-language instruction in schools and employment of Hispanic teachers.

"[2] This blended style of education, or "Americanization with kindness" was revolutionary at a time when Southwestern schools punished students for speaking Spanish.

[2] Her half-sister Anita Bergere succeeded her in this position, after Otero-Warren chose not to run for reelection after controversy developed in 1927 that she held a conflict of interest serving as a local sales representative for the textbook purveyor Houghton Mifflin Company.

[2] After ending her tenure as Superintendent of Instruction, Otero-Warren continued to pursue opportunities to integrate ethnic cultures and languages into the public school curriculum of New Mexico.

She also created a program at Borinquen Field for sailors, soldiers, Air Force, and marines in the United States to familiarize them with the Spanish language.

[2] In her writing, Mexicans in Our Midst: Newest and Oldest Settlers of the Southwest, she illustrated the beauty of her homeland and culture to a vast audience.

[2] By 1947 she began her real estate business in Santa Fe named Las Dos Realty and Insurance Company with Meadors.