from 1983 to 1989 and was named Civil Libertarian of the Year, Central Texas ACLU, 1990 and was in-house District Counsel for the Communications Workers of America in Austin from 1981 through 1984; he continued serving as District Counsel for CWA after co-founding a private law firm in 1984, and remains CWA's District Counsel for its five-state District 6. His primary professional concentration has been in classical labor law and workers' rights on the side of unions, serving as legal counsel and trial attorney for a number of labor unions at the international and local union levels over the space of 33 years and continuing at the current time. Other major labor clients of Van Os have included Steelworkers (USW), Carpenters (UBC), Electrical Workers (IBEW), Sheet Metal Workers, Fire Fighters, Musicians (AFM), Deputy Sheriffs of Bexar County, Texas AFL-CIO, and others. Van Os and his wife, Rachel, met on a CWA picket line in 1993. In the 1980s and early 1990s he also represented the NAACP and LULAC in a series of controversial voting rights lawsuits and desegregation suits involving the City of Austin and the Austin Independent School Board. While in law school and in the early years of his career Van Os was mentored in the practice of law by prominent Texas labor and civil rights attorneys Sam Houston Clinton (later a long-serving Judge on the Texas Court of Criminal Appeals) and David R. Richards. He spent the first 23 years of his legal career in Austin before he and Rachel moved their growing family to San Antonio in 1999. After moving to San Antonio he continued to be involved in high-profile issues such as obtaining a temporary restraining order on behalf of the American Federation of Government Employees (AFGE) that temporarily halted the unpopular closing of Kelly Air Force Base. Another prominent client was Bill Burkett in the Killian documents affair, later known as Rathergate, of 2004. Van Os continued to advocate for constitutional rights, civil rights, and worker rights as an active legal counselor and litigator. He was the owner and managing attorney of the law firm of David Van Os & Associates, P.C., of San Antonio Texas. The law firm consists of two attorneys, Van Os and his associate Matt Holder, concentrating in Constitutional law, union-side labor law, and civil rights. Political history 1998 Texas supreme court bid In 1998, Van Os was the unsuccessful