WASHINGTON — Julián Castro’s plan to decriminalize unauthorized border crossings has splintered an expansive Democratic presidential field, pitting the former San Antonio mayor, in particular, against fellow Texan Beto O’Rourke.

But the proposal has also divided Texas Democrats in Congress.

Some lawmakers want to repeal the existing criminal statute, with Houston Rep. Sylvia Garcia decrying what she called “inherently racist, harmful laws.” Others disagree, with Dallas Rep. Colin Allred saying that “people coming to the U.S. should do so legally and responsibly.”

Conflict among even those allies spotlights an intensifying tug-of-war for the heart and soul of the Democratic Party, where progressives in the 2020 race and beyond are pushing the conversation further to the left on critical issues like immigration, health care and tax policy.

Adding to the tension is the fact that Republicans, who abhor the decriminalization plan, are eager for any and all opportunities to accuse Democrats of supporting “open borders.”

While Castro and other like-minded liberals reject that kind of critique, the split over illegal border crossings nevertheless stands out in an immigration debate in which Texas Democrats otherwise tend to agree on the pitfalls and potential solutions.

They demand legal status for Dreamers, those immigrants brought to the U.S. illegally as children. They want to better support beleaguered Central American countries. They criticize President Donald Trump for his barbed rhetoric and hard-line border security tactics.

“Our border enforcement is failing because the Trump administration is cruel and using enforcement in a punitive manner while worsening the crisis in Central America,” said Rep. Marc Veasey of Fort Worth.

Presidential hopeful Julián Castro's plan to decriminalize unauthorized border crossings has divided Texas Democrats in Congress. (Chip Somodevilla / Getty Images)

Castro’s decriminalization push has become a signature element of his long-shot presidential bid, with the Texan arguing that it’s necessary to stop migrant family separations at the border.

He wants to repeal part of immigration law — Section 1325 — that makes it a misdemeanor to enter the U.S. without authorization. He would instead rely on the existing option to treat the incidents as civil offenses, which still carry real consequences and could include the possibility of deportation.

Castro has been cheered by many immigration rights advocates, while also winning over presidential rivals like Massachusetts Sen. Elizabeth Warren and New Jersey Sen. Cory Booker.

Other White House hopefuls remain unconvinced, particularly as officials such as Sarah Saldaña, President Barack Obama's director of Immigration and Customs Enforcement, and Jeh Johnson, Obama's Homeland Security secretary, have balked at removing such a deterrent.

O’Rourke has explained that he wants to “retain some part of 1325 to criminally prosecute people we apprehend who are known smugglers, whether or not they're in the act of smuggling at the moment, or known traffickers, whether or not they're in the act of trafficking at the moment.”

The dispute has led to titanic clashes in the first two sets of Democratic debates.

In one, Castro ripped into O'Rourke, a former El Paso congressman, by saying, "You should do your homework on this issue." In another, Castro jabbed at former Vice President Joe Biden, saying that what America needs are "politicians who actually have some guts on this issue."

The former U.S. housing secretary has also extended his push, albeit with less notice, by proposing to repeal a sister statute, Section 1326, that makes illegal reentry a felony.

Last month, he told the Huffington Post that he would like to see those instances also "treated as a civil matter," explaining that a dismantling of the companion sections would "close off every opportunity that any future administration may have to exercise such cruelty."

Rep. Sylvia R. Garcia, D-Houston, said the existing statutes that criminalize illegal border crossings are "inherently racist, harmful laws." (Susan Walsh / The Associated Press)

But an act of Congress is needed to get any of that done.

The idea is a no-go in the GOP-run Senate, where conservatives accuse Democrats of doing little to address the migration crisis. Prospects are murky even in the Democrat-run House, which flipped control this year largely on the strength of centrist Democrats unseating incumbent Republicans.

To get a sense of where Texas Democrats in Congress stand on decriminalizing illegal border crossings, The Dallas Morning News queried all 13 of those lawmakers.

Perhaps signaling the fraught nature of the debate, the offices of Reps. Lloyd Doggett of Austin, Veronica Escobar of El Paso, Lizzie Fletcher of Houston, Al Green of Houston and Sheila Jackson Lee of Houston didn’t respond to repeated requests for comment.

A spokeswoman for Rep. Henry Cuellar of Laredo declined to comment.

Others, however, responded with clarity. San Antonio Rep. Joaquin Castro — Julián Castro’s twin — shares his brother’s positions, as one might expect. Garcia, a freshman lawmaker, offered one of the more impassioned arguments for decriminalizing border crossings.

“It is time to decriminalize the immigration system that has left countless children with a lifetime of trauma,” Garcia said, advocating for repeal of both Sections 1325 and 1326.

The Houston Democrat noted that the laws, which date to the 1920s, were "first introduced by members of Congress who were explicitly motivated by racism and eugenics." She also pointed out that the criminal statutes were rarely enforced for decades, at least until around 2005.

“People seeking the American dream are far from the greatest crime threat the country faces,” she said.

Rep. Colin Allred, D-Dallas, disagrees with the decriminalization plan, saying that "people coming to the U.S. should do so legally and responsibly. (Brian Elledge / Staff Photographer)

McAllen Rep. Vicente Gonzalez, in turn, said he’s “not for ‘open borders’” or “for people just coming in” into the U.S. without consequences. But he said the existing criminal statute was abused by Trump and “turned into very harsh conditions that are still out there at the border.”

He and Brownsville Rep. Filemon Vela support repealing Section 1325. Those two are uncertain about what to do about Section 1326.

“I’ve gotta think a little bit about that,” Gonzalez said, referring to the law covering illegal reentry. “You need to learn your lesson at some point, right?”

Other Texas Democrats oppose repealing either statute, highlighting the ideological expanse in the delegation. Among them is Allred, a freshman lawmaker who's endorsed Castro for president.

“Instead of focusing on these individual provisions, we need to finally enact comprehensive immigration reform that secures our border, meets the needs of our economy and provides a pathway to citizenship for those who are here working hard and paying taxes,” he said.

Longtime Dallas Rep. Eddie Bernice Johnson said that “it is important that we know who is entering our country.”

“I do not believe it would be wise to repeal either of these sections in our immigration code unless included in a wide-ranged, comprehensive immigration reform plan aimed at fixing our broken system,” she said, also citing a need to address migrants’ treatment by ICE and others.

Veasey, the Fort Worth Democrat, said lawmakers “don’t have to change any laws for Trump to stop ripping families apart and stop putting kids in cages.”

“If we offered a fair and compassionate path to migrate legally for those seeking safety at our border, then I believe the issue of decriminalizing unauthorized border crossings would quickly become moot,” he said.