(CNN) Sen. Bernie Sanders said Friday that the recent attacks on a Texas candidate for Congress by the Democratic Congressional Campaign Committee are "absolutely unacceptable."

During an interview with CNN's Jake Tapper at the South by Southwest tech and media conference in Austin, Texas, Sanders shared his views on the ongoing battle in Texas between the DCCC, the party's political arm for House races, and Laura Moser, a journalist and activist who is in the running to challenge Republican Rep. John Culberson this fall.

"I detest that type of politics, and I think most Americans do," the Vermont independent said. "And then when you have the DCCC actually doing opposition research on a serious and strong candidate for the US Congress, when the Democratic establishment itself is engaging in negative attacks against a responsible candidate, that is absolutely unacceptable."

The Democratic House primary in the Houston area has become a stand-in for the broader battle within the party between progressives, who backed Sanders, and members of the establishment. Our Revolution, the political organization that controls Sanders' massive email list, has endorsed Moser.

The Democratic Congressional Campaign Committee dug up a 2014 Washingtonian article in which Moser wrote that she'd "sooner have my teeth pulled out without anesthesia" than live in Paris, Texas. Progressive activists were incensed to see the group weigh in with such a heavy hand less than three weeks from the March 6 contest.

"It was outrageous," Sanders said of the committee's attacks on Moser.

Moser ended up as one of the two highest vote-getters and heads to a runoff in the primary.

Sanders expressed optimism, however, about the possibility of Texas, a traditionally Republican state, electing Democrats in 2018.

"If you in Texas are prepared to work hard, stand up, fight back, go out to your neighbors, talk to those people who voted for Trump, make sure that every friend you have and every family member you have comes out to vote," Sander said, "I believe Texas can go blue."

Sanders said Republicans are able to win in states like Texas when "voter turnout is low and big money buys elections."

"If we can raise voter turnout, if 50% of the people come out in a midterm election, one out of two people, that's not asking for much," he said. "Democrats will win in Texas and in every other state in this country."

But on Tuesday, Texas' primary provided little evidence to support Sanders' hopes.

With over 99% of precincts counted, Democratic turnout topped 1 million in a midterm primary in the state for the first time since 2002. Republicans, on the other hand, cast 1.5 million votes in their primary. In other words, 60% of all votes cast in Tuesday's primary went to Republican candidates.

Rep. Beto O'Rourke won the state's Democratic primary election, emerging as Sen. Ted Cruz's challenger this fall. If O'Rourke wins, he will be the first Democrat to win a statewide election since 1994 and the first Democrat elected to the Senate from Texas since 1988.

CNN has downgraded that race from Solid Republican to Likely Republican.

Sanders made the case to Texas voters that what he described as the current Republican agenda is not in line with the majority of Americans' beliefs.

"The Republican agenda of tax breaks for billionaires, throwing millions of people off of health care, cutting Social Security and Medicare and Medicaid ... is an agenda supported by relatively few people," he told Tapper.

Sanders also weighed in on Nation of Islam leader Louis Farrakhan's recent anti-Semitic speech in Chicago.

Asked by Tapper what he thought about the left's hesitation in condemning Farrakhan's speech, which included things like "the powerful Jews are my enemy" and "Satanic Jews," Sanders said:

"Racism is not acceptable. Religious bigotry against Muslims or Jews or anybody else is not acceptable."

Sanders told Tapper he would "take on" Farrakhan or anybody else who espouses such views.

"We as a nation have got to do everything that we can to fight anybody, whether it's Trump, Farrakhan or anybody else, who is trying to divide us up," he said.