Democratic presidential contender Julin Castro challenged all the 2020 candidates for the nomination Wednesday to get behind his call to repeal the law that the Trump administration used to systematically separate families at the border last year.

The former secretary of housing and urban development was the first candidate to issue a comprehensive immigration plan when he did so in April, taking the trailblazing step of calling for the repeal of illegal entry, the federal criminal offense of crossing the border without authorization.

Castro contended that the federal government should instead rely on the civil immigration system, which enforces the penalties of detention and deportation, to regulate border crossings. Illegal entry was first criminalized in 1929, but it is only since the George W. Bush administration that criminal prosecutions of migrants have become a priority for the Justice Department. Since 2008, immigration prosecutions have taken up about half of the federal criminal docket a trend that has increased since President Donald Trump took office.

Heres why its important, Castro said. We see all this horrendous family separation. They use that law, Section 1325, to justify separating little children of their families. So I want to challenge every single candidate on this stage to support the repeal of Section 1325.