Donald Trump has long had a clear message on illegal immigration: He’s against it. But he hasn’t had a clear policy on what to do about it and it’s finally catching up to him.

Trump set off a wave of speculation after he met with Hispanic supporters on Saturday, some of whom came away hopeful he might soften his opposition on legalizing undocumented immigrants. Rather than tamp down the speculation, his campaign reacted ambiguously.

“To be determined,” campaign manager Kellyanne Conway told CNN when asked whether Trump still favored a new “deportation force” to remove undocumented immigrants.

Trump told Fox News on Monday that he was “not flip flopping,” on the issue but offered no specifics as to his current position. Adding to the confusion, the campaign postponed an upcoming speech in Denver that was expected to address his immigration policy on Thursday.

In a later appearance with Fox News' Bill O'Reilly, Trump went into more detail, but his statements provided little insight into whether he was softening his position on deportation. He said he would enforce existing laws "perhaps with a lot more energy" and "get rid of all the bad ones," citing President Obama's own record of deporting undocumented immigrants as a model.

But deporting criminals is relatively uncontroversial. The bigger fight between Obama and his critics was over executive orders to prioritize criminals for removal, grant work permits to young undocumented immigrants, and -- until he was stymied by the courts -- shield millions more from deportation. Trump did not explain how he would handle non-criminal cases like these himself, saying only that he would "follow the process."

Trump also seemed confused about how the deportation process works. He told O'Reilly that he would not house suspected illegal immigrants in "detention centers" while their cases were adjudicated. "I've never heard the term," Trump said. "I'm not going to put them in a detention center."

In fact, there already are immigration detention facilities all over the country that Congress requires the administration fill up with 34,000 people at all times. Trump's own immigration plan -- which is still on his website -- states that illegal border crossers "must be detained until they are sent home, no more catch-and-release."

To understand why Trump’s campaign is tying itself into knots this week, you have to understand the last few years of debates over immigration reform.

The issue that’s caused by far the most heartburn for Republicans is the one that’s tripping up Trump today: Whether to grant legal status, and possibly citizenship, to undocumented immigrants living in America. It's the one that pins GOP candidates awkwardly between Latino voters and business groups on one side, who favor a path to citizenship, and talk radio and nativist voters, who see any policy short of deportation as “amnesty.”

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Trump’s border wall is his most famous proposal, but it’s actually a relatively minor part of the immigration debate by comparison. Democrats would almost certainly accept a new barrier in exchange for GOP votes on a path to citizenship. This isn’t a hypothetical scenario: The “Gang of Eight” immigration reform bill that passed the Senate in 2013 included an amendment requiring 700 miles of new fencing along with 20,000 extra border patrol agents in order to attract conservative support.

Given the political sensitivities around the issue, many Republican politicians who opposed the “Gang of Eight” bill avoided pinning themselves down on legal status for fear of alienating potential supporters or poisoning future negotiations. Senator Ted Cruz pointedly refused to rule out legalizing immigrants for years before finally bowing to conservative pressure and doing so in the presidential primary season.

Trump cannon-balled into this carefully worded debate in 2015 with a series of confusing statements and outrageous boasts that went far beyond what even the most ardent anti-immigrant politicians had proposed.

Not only was Trump against “amnesty,” he bragged to Republicans he would remove all undocumented immigrants in a period of “18 months to two years.” He told MSNBC’s Morning Joe this would be accomplished using a “deportation force.” Asked by NBC News Chuck Todd as to whether he’d break up millions of mixed-status families that include both American citizens and undocumented immigrants, Trump responded that “they have to go.”

Like Trump’s call to punish women who have an abortion, which he retracted after realizing pro-life groups opposed to the concept, he seemed to be telling hardliners what he thought they wanted to hear rather than what anyone had demanded.

For conservatives, the primary alternative to legalization when Trump entered the race was “self-deportation,” a strategy put forward by Mitt Romney in 2012 that would encourage immigrants to leave on their own by restricting their access to work, transportation, and housing. Few public figures called for mass deportations, let alone a crackdown so sweeping that it could be accomplished in under two years.

“His first reaction was ‘Illegal aliens gotta go!’ in a kind of barstool opinionating sense, like your uncle George at the Thanksgiving dinner table,” Mark Krikorian, executive director of the Center for Immigration Studies, which favors lower levels of immigration said. “What he seems to be doing now is backing into an actual policy that’s real.”

Notably, Trump’s most concrete positions on deportation have come from offhand comments. His written plan called for a major increase in immigration enforcement agents, an end to birthright citizenship, and a renewed focus on undocumented immigrants with criminal records, but was vague on broader legalization issues.

Trump himself seemed uncertain about his position. In the same NBC News interview in which he pledged to deport DREAMers brought to America as children, he said he would “bring them back rapidly, the good ones” after the deportations were complete. It was an odd position that he repeated at several points -- arguing for the removal of an estimated 11 million people in ways that likely require an expensive, disruptive, and Constitutionally questionable enforcement regime only to invite them right back into the country.

Trump has never seemed to have much of a firm take on the legalization issue. While he has long championed a border wall, he has also sounded like a dove on what to do about existing undocumented immigrants in the run-up to his presidential campaign.

In 2012, for example, he floated a “permanent solution” on Fox News in which some immigrants would remain. “We have to have some compassion, we can’t just throw everybody out,” he said.

After Romney lost that November in thanks in part to strong Democratic margins with Latino and Asian voters, Trump lashed out at his “crazy policy of self-deportation” in an interview with Newsmax. As late as August 2013, Trump told NBC News’ Kasie Hunt he wasn’t sure about his position on the recently passed “Gang of Eight” bill or whether he might support portions of it. “I actually think it's too early to say,” he said.

Even at Trump’s most nativist in 2015 and 2016, he stressed he wanted a gentle approach, or as gentle as one could be while forcibly tearing parents from their children. “You're going to have a deportation force and you’re going to do it humanely,” he told MSNBC last November.

If the Hispanic supporters he met with on Saturday were confused by his relatively soothing tone on the issue, they wouldn’t be the first ones.

In August 2013, immigration activist Gaby Pacheco helped organize a meeting between Trump and DREAMers in the hopes of earning his support for policies that would allow them to stay in the country. They left with the strong impression that Trump, who lavished them with gifts from his line of branded products afterwards, had endorsed their plan. “You’ve convinced me,” Trump said, according to a meeting participant’s account to NBC News at the time.

Looking back now, Pacheco views the meeting differently.

“We left there feeling so excited,” she said. “I feel like such a fool.”

Pacheco recalled that Trump seemed to have a weak grasp on the issues – he seemed to believe they were undocumented by choice before they explained there was no clear way for them to earn legal status, a problem they hoped to address through legislation. Comments he made that sounded supportive sounded confused in retrospect in ways that resembled his disjointed speaking style as a presidential candidate.

“The first thing you see on TV, the first thing you see in his speeches, is that you have to be quick on your toes to understand what he’s saying, because he goes from point to point and doesn’t finish his sentences,” she said. “At the time we were meeting with him, he was just throwing out every idea in his head.”

Trump also seemed preoccupied with other concerns, asking them what they thought about future Republican rivals like Governor Chris Christie and Senator Ted Cruz and whether they would win Hispanic voters. Pacheco said she and her fellow activists had to struggle to turn the topic back to immigration, where activists explained their personal battles with their undocumented status.

“It was the Donald Trump everybody now in America has gotten to know,” she said. “He tells you exactly what you want to hear.”