It's been a central element of his campaign.
Build a wall. Make Mexico pay for it. And expel everyone living in the U.S. illegally with the help of a "deportation force."
But now, with just 10 weeks to go before Election Day, Republican presidential candidate Donald Trump seems to be waffling on his once adamant stance on immigration.
At a Fox News town hall taping last week, in the face of pressing questions, he proceeded to poll the audience at length on the fate of an estimated 11 million people.
Trump is now planning a major speech Wednesday in Phoenix, during which he's expected to finally clarify his stance. Supporters are hoping for a strong, decisive showing. But for critics, many already disposed to vote against him, his wavering on what has been his signature issue seems like a warning that he's unable to handle a central element of any president's job — making decisions.
It also underscores how little his Republican campaign has invested in the nitty-gritty of outlining what he would do as president, especially when compared with the more detailed plans of his Democratic rival, Hillary Clinton.
"It's just puzzling," said Lanhee Chen, who has served as a policy adviser to several Republican presidential candidates. "This is the issue on which he rose to prominence in the primary and the issue on which he continues to stake much of his campaign."
From the start, Trump has never been the kind of candidate to pore over thick policy books.
Indeed, he has mocked Clinton on the subject.
"She's got people that sit in cubicles writing policy all day. Nothing's ever going to happen. It's just a waste of paper," he told Time Magazine in June. "My voters don't care and the public doesn't care. They know you're going to do a good job once you're there."
To date, Trump's campaign has posted just seven policy proposals on his website, totaling just over 9,000 words. There are 38 on Clinton's "issues" page, ranging from efforts to cure Alzheimer's disease to Wall Street and criminal justice reform, and her campaign boasts that it has now released 65 policy fact sheets, totaling 112,735 words.
"I've laid out the best I could, the specific plans and ideas that I want to pursue as your president because I have this old-fashioned idea," Clinton said during a recent speech in Colorado. "When you run for president, you ought to tell people what you want to do as their president."
Trump's new campaign manager, Kellyanne Conway, has said she's pushing her boss to get more specific. Yet his positions on a host of issues remain vague at best.
For example, while Trump has slammed the Common Core education standards and touts the benefits of local control of education, he has no formal, detailed plans for improving public schools. He talks about student loan debt and the increasing costs of higher education, but has yet to propose solutions. He has teased plans to make childcare more affordable, but has missed his own deadline for unveiling them.
Until recently, however, there has been no doubt about where Trump stood on illegal immigration. The wall was going up — Mexico would have to pay — and those estimated 11 million people living in the country illegally were going to have to leave.
But over the summer, Trump began suggesting in closed-door conversations with Hispanic leaders that he might be open to softening his stance. On August 20, he convened round table of Hispanic lawmakers and business leaders, and left some with the same impression. The day after, campaign manager Conway said his position on deportations was "to be determined."
Trump's supporters say questions about his recent waffling are overblown. His running mate, Mike Pence, describes him as "a CEO at work" as he consults with various stakeholders.
"You see someone who is engaging the American people, listening to the American people," Pence told CNN on Sunday. "He is hearing from all sides."
But Stephen Moore, a conservative economist who has worked with Trump to shape his tax and economic plans, says the vagueness on Trump's economic policies was by design.
"We want to talk about the big visionary stuff. We don't want to have a big debate about this loophole, that loophole," he said. "This is a campaign, it's not a write-up of a tax bill in the Ways and Means Committee."
Ari Fleischer, a White House press secretary under George W. Bush, says the confusion that now exists about Trump's plans for immigration underscores "the risk in electing someone whose candidacy is based on his personality and image, as opposed to his experience and policy knowledge."
While Trump could succeed as president as a "big picture, set the tone, drive the direction and move the government" kind of leader, Fleischer said that would require him to surround himself with a knowledgeable and capable staff.
"But the lesson in how he's run his campaign — and frankly in how he's run his businesses — doesn't give you confidence that he would surround himself with a lot of capable people," he said.
Based on reporting by The Associated Press.