From Texas Public Radio:
Moderate and progressive candidates are mired in a nationwide struggle that may define the future of the Democratic Party.
One of the starkest examples of that ideological and political struggle can be found in the 28th Congressional District in South Texas, which spans from San Antonio to the border cities of Laredo and McAllen.
Henry Cuellar has represented the district for 15 years and the self-identified moderate Democrat has the backing of House Speaker Nancy Pelosi and more than 100 local leaders.
But he faces his first serious primary challenge from Jessica Cisneros, a 26-year-old immigration attorney and progressive backed by presidential candidates Bernie Sanders and Elizabeth Warren.