The overwhelming majority of Tejanos were pro Union, esp small farmers, landless peasants, or laborers. There were a small number of landowners who tended to ID as "Spanish" rather than Mexican and looked down upon other Mexicans. A couple of them were prominent during Reconstruction as Redeemers.
That kind of self loathing hasn't entirely ended. You even have a few Latinos in the KKK today, who are lightskinned enough to "pass," don'gt speak Spanish or even have an accent, etc.
IOW, if you can find a coconut (the Latino version of an Oreo) who will be accepted by white Southern racists who want to pat themselves on the back for not being completely racist....the coconut could get elected.
Perhaps Thomas Rodriguez.
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From Encyclopedia of Latino/a History
Rodriguez, Thomas (1839-1903). State congressman
A member of the educated Tejano elite, Rodriguez was one of the few Latinos to hold political office after Reconstruction, positions he always gained and held by alliances with Anglo ex-Confederates. Coming from the Mexican state of Tamaulipas, his father was an officer in first the Spanish and later the Mexican Army, his mother from San Antonio. Rodriguez was educated at the University of Northern Pennsylvania. Before the Civil War he served in the Bexar County offices of county clerk and then tax collector.
Like many other Tejano elites, Rodriguez joined the Confederate Army as an officer. (Landless Tejanos tended to be pro-Union, neutral, or were drafted into or joined Confederate militias out of fear of reprisals.) He served first as lieutenant of an independent company, later as adjutant and commissary in a company led by Colonel Santos Benavides, the highest ranking Tejano in the Confederate Army. Rodriguez took part in battles against the legendary Juan Cortina and other Tejanos, was part of three invasions of Mexico, and helped keep the Rio Grande open for shipments of Confederate cotton. Still, despite the efforts of Rodriguez and Benavidez, Tejano Union resistance against the Texas Confederates continued throughout the war, primarily in South Texas, where Unionist Tejanos harassed Confederate troops and seized cotton and stock for Union forces. After the war, ex-Confederates did all they could to subvert Republican rule in the state, yet most Tejanos kept their Union sentiment and sympathized with Radical Reconstruction.
Rodriguez, as an ex-Confederate and Democrat, worked with and benefited from the work of the “Redeemers,” those working to keep the old order and for the victory of white supremacy at the ballot box where they had failed on the battlefield. At the end of the war Rodriguez was elected assessor and collector for Bexar County. He was appointed to the Board of School Examiners in San Antonio in 1867. Rodriguez served three terms as a state congressman for parts of Atascosa, Karnes, and San Patricio Counties. He faced no effective Republican opposition in any of these elections because widespread violence and intimidation led to the loss of the rights to vote or run for office for most Union supporters during Reconstruction. Only one third party candidate ever gave him anything close to effective opposition. Rodriguez served on various House committees, including Irrigation, Agricultural Affairs, Town and City Corporations, Federal Relations, County Government and County Finances, and Privileges and Elections. After him there were few Tejanos in political office, outside of Cameron County, for a generation. A state resolution upon his death praised him for loyalty to the state of Texas and the Democratic Party, but made no mention of any work benefiting Tejanos.