WASHINGTON - U.S. Rep. Filemon Vela took a poison pen to the Republican presumptive presidential nominee, Donald Trump, in an open letter Monday morning.

"Mr. Trump, you’re a racist and you can take your border wall and shove it up your ass," the Brownsville Democrat wrote in a lengthy missive to the real estate magnate.

Jonathan Ernst / Reuters Donald Trump holds a rally with supporters in Albuquerque, New Mexico, on May 24, 2016.

Vela notes in the letter that he agreed with Trump on some policies, like improving veterans care, addressing Mexican drug cartels and deporting criminal felons who are in the country illegally. But then he savages Trump for his rhetoric on those of Mexican descent and his promise to build a wall on the southern U.S. border.

"While you would build more and bigger walls on the U.S.-Mexico border, I would tear the existing wall to pieces," Vela wrote. "Why any modern-thinking person would ever believe that building a wall along the border of a neighboring country, which is both our ally and one of our largest trading partners, is frankly astounding and asinine."

Vela then defended U.S. District Court Judge Gonzalo Curiel, the judge overseeing litigation related to Trump's education enterprise, Trump University, with fraud. Trump has questioned Curiel's capacity for fairness based on his Mexican heritage. Curiel was born in Indiana.

Vela then pointed out that his own family lineage in the United States goes back farther than Trump's paternal grandfather.

"Before you dismiss me as just another 'Mexican,' let me point out that my great-great grandfather came to this country in 1857, well before your own grandfather," he wrote. "His grandchildren (my grandfather and his brothers) all served our country in World War I and World War II. His great-grandson, my father, served in the U.S. Army and, coincidentally, was one of the first 'Mexican' federal judges ever appointed to the federal bench."

"I will not presume to speak on behalf of every American of Mexican descent, for every undocumented worker born in Mexico who is contributing to our country every day or, for that matter, every decent citizen in Mexico," he added.

U.S. Rep. Filemon Vela, D-Brownsville, is speaking at the 2016 Texas Tribune Festival. Find out more at texastribune.org/festival



This article originally appeared in The Texas Tribune.