The Democratic presidential candidate Julián Castro will not rule out direct payments to African Americans in reparation for the legacy of slavery – a stand that separates him from his 2020 rivals.

“If under the constitution we compensate people because we take their property, why wouldn’t you compensate people who actually were property,” the Obama-era housing secretary and former mayor of San Antonio told CNN’s State of the Union on Sunday.

Castro was among a pack of 2020 candidates to speak this weekend at the South by Southwest Festival in Austin, Texas, in one of the biggest gatherings of the Democratic field yet.

Other candidates are discussing the benefits of tax credits and other subsidies rather than direct payments for the labor and legal oppression of slaves and their descendants. The Vermont senator Bernie Sanders, for example, wants to put resources such as Medicare for All and tuition-free college into distressed communities.

Quick Guide Who are the leading Democrats running for 2020? Show Joe Biden, former vice president Biden unsuccessfully ran for the nomination in 1988 and 2008, and his campaign is likely to be dogged by controversy after allegations from several women they were left feeling uncomfortable by their physical interactions with him. If successful, Biden would become the oldest person to be elected president in US history. Mike Bloomberg, former New York mayor Bloomberg has expressed concern that none of the top candidates can defeat Trump, and he aims to make up for an unusually late entry in the Democratic primary with historic spending of hundreds of millions of dollars in television ad time and an unorthodox strategy of skipping the first four states in the primary. Bloomberg has announced that his campaign will be entirely self-funded, but can this billionaire win? Amy Klobuchar, Minnesota senator On Election Night 2018, Klobuchar coasted to a third term as senator in a state Trump almost won. Next morning she was on every short list of potential presidential candidates. Supporters say her success with rural voters makes her a formidable candidate in the Rust Belt, while her calm demeanour provides a clear contrast with Trump. Bernie Sanders, Vermont senator Sanders turned a long-shot, anti-establishment bid for the presidency into a “political revolution” that energized the party’s progressive base. His political career began nearly 40 years ago, but it wasn’t until his 2016 run that Sanders became a national figure as a new generation of Democrats – and 2020 contenders – embraced his populist economic policies. Elizabeth Warren, Massachusetts senator Her sharp criticism of Wall Street and big corporations has made Warren a favorite among progressive activists, and she will campaign on a message of a rigged economic system and income inequality.

Castro said he did not think that was the proper argument against reparations.

“It’s interesting to me,” he said, “that when it comes to Medicare for All, healthcare, the response there has been, ‘We need to write a big check’. That when it comes to tuition-free or debt-free college, the answer has been, ‘We need to write a big check.’

If we compensate people because we take their property, why wouldn’t you compensate people who actually were property? Julián Castro

“And so, if the issue is compensating the descendants of slaves, I don’t think that the argument about writing a big check ought to be the argument that you make, if you’re making an argument that a big check needs to be written for a whole bunch of other stuff.”

He did not say that if elected he would push for direct compensation to descendants of slaves, saying instead he would appoint a commissioner or taskforce to make recommendations.

On Saturday night, a Des Moines Register/CNN/Mediacom Iowa poll concerning the Democratic field put Castro at 1% support. The poll winner, former vice-president Joe Biden, at 27%, has not yet declared his candidacy.

Castro told CNN he was “articulating a strong, compelling vision for the future of this country” and said he could tell he was “going to gain traction”.