By Rachel Reyes, The New York Times.This spring I saw Markwayne Mullin's confirmation hearing to become U.S. Secretary of Homeland Security. It was probably the first confirmation hearing I ever saw in my life. I've never been a political person. I saw her because Mullin's words were of personal interest to me. In 2025, an Immigration and Customs Enforcement (ICE) agent killed my son, Ruben Ray Martinez, in Texas. I was 23 years old, he was a qu…