Martin O’Malley, Democratic presidential candidate and former governor of Maryland, is a mere whisper in the polls and has been pilloried for his record on policing while he was mayor of Baltimore. He also happens to be an immigrant voter’s dream.

Compared to other Democratic presidential candidates who’ve incrementally evolved on the issue of immigrant rights, and contrasted against a sea of Republican candidates who clamber to say the most outrageously racist thing, O’Malley is a standout for his longtime support of immigrants’ rights. And for the seriousness of his current reform platform.

“Certainly compared to any of the other Democrats and all of the Republicans, [O’Malley’s platform] is so far more detailed and thorough than anyone else has been willing to express,” said Beth Werlin, director of policy at the Immigration Policy Center. Werlin said that on immigrant detention in particular, where O’Malley has proposed serious cutbacks, “he really goes out there in a level we haven’t seen from other candidates.”

Maryland activists say O’Malley’s leadership on immigration issues started with his time as mayor of Baltimore. “I remember in 2006 when we had a huge fight about the day laborer situation in Baltimore, O’Malley came to the town meeting with an attitude of: I’m going to resolve this,” Gustavo Torres, the executive director of CASA de Maryland, a statewide immigrant rights advocacy organization, told me. “Six months later we had a day laborer center.”

Torres ticked off the other issues O’Malley, as governor, later backed: driver’s licenses for undocumented immigrants; Maryland’s state Dream Act, which allowed undocumented students to pay in-state tuition in public colleges; an initiative disentangling local law activities from immigration enforcement.

O’Malley, it should be noted, wasn’t always an unequivocal backer of these policies. He signed a state law making permanent a two-tiered system granting driver’s licenses to undocumented immigrants in 2013. But four years before that, he hedged on the policy when faced with pushback from the federal government, The Washington Post reported this summer. Former Maryland delegate Luiz Simmons complained to the Post that O’Malley “has a tendency to jump on the caboose of the train as it’s pulling out of the station and put on a conductor’s hat and walk to the front.”

That said, driver’s licenses have been a more thorny topic for Hillary Clinton. Last week, former New York governor Eliot Spitzer said he killed a 2007 driver’s license plan in his state at the request of Clinton, then a New York senator preparing for her 2008 presidential campaign. The moment was illustrative of her waffling support for immigrant rights, Spitzer said. He’s backing O’Malley in this primary.

Torres remembers a much more recent moment of contrast between the two candidates. Last summer, when the country was in the throes of a child migrant crisis, Clinton said of tens of thousands of unaccompanied children fleeing Central America: “They should be sent back.” The United States must “send a clear message [that] just because your child gets across the border doesn’t mean your child gets to stay,” Clinton said last year. As cable news streamed images of Border Patrol agents apprehending children and families at the border, O’Malley, then just a rumored presidential candidate, struck a different tone. “We are not a country that should send children away and send them back to certain death,” he said, calling “hospitality to strangers” an “essential human dignity.”

Now, as an official candidate, O’Malley has worked to solidify his immigration reputation with a stunningly explicit immigration platform. He doesn’t stop at mere support for comprehensive immigration reform—an almost empty political position for Democrats, given the fact that reform has been trapped in Congress for over a decade. O’Malley also details his policy proposals in the likely scenario that Congress does not pass immigration reform in the near future—a reality that newly minted Speaker Paul Ryan further cemented during his tour of this week’s Sunday morning talk shows, when he vowed he wouldn’t work with the Obama administration on immigration.

O’Malley lays out in his platform ideas on immigration enforcement (more restraint), detention (only as “a last resort”), healthcare (yes for those who are eligible for executive action relief), even technical specifics like how to work around a policy mandating that those eligible for green cards face a decade-long exclusion from the United States before taking advantage of the legalization process. The policy ideas include actions that he can take without Congress (absent, of course, the legal battles that have tied up President Obama’s latest executive action). It’s not a safe wait-and-see approach to campaigning. It’s rather bold, in fact.

While comprehensive immigration reform languishes in Congress, “families are feeling the devastating impact of deportation policies on a daily basis,” Gabriela Domenzain, Martin O’Malley’s director of public engagement told me. “What the new American immigrant community in the United States wants is specificity.”

Thus far Clinton’s, O’Malley’s, and Bernie Sanders’s engagement on immigration has largely involved them agreeing with one another that the Republicans are racist and that they support comprehensive, Congress-driven reform. Clinton and Sanders have both pledged to “go further” than President Obama did in his contested executive order offering undocumented parents of American citizen or green card–holding children short-term work permits and temporary shields from deportation. Clinton and Sanders, along with O’Malley, have agreed to also examine other groups of people who could qualify for relief from similar kinds of executive action, like undocumented parents of some undocumented children. Clinton, too, has pledged to end privately run detention centers.

Thus far though, the candidates haven’t been forced to delve as deeply on these topics as has O’Malley in his platform. So Sanders and Clinton may well come to the same place on enforcement and detention policy as O’Malley, Werlin of Immigration Policy Center notes. But O’Malley got there first, without pressure, and has been there for a while.