On immigration, Trump’s quick fix was building a wall. And he hawked it endlessly, in part because it allowed him to sidestep the public-policy debate that had been tearing the GOP apart: what to do about the undocumented already in the U.S. Trump rarely mentioned deportation, perhaps because he sensed it would draw him into the public-policy quagmire he wished to avoid.

In his June 16 announcement speech, Trump famously said that Mexicans were “bringing drugs. They’re bringing crime. They’re rapists.” But despite referencing immigrants already in the United States, Trump said nothing about what to do with them. His only immigration proposal was to “build a great, great wall on our southern border. And I will have Mexico pay for that wall.”

At the first GOP debate on August 11, Trump again declared that, “We need to build a wall, and it has to be built quickly.” Scott Walker, Ted Cruz, and Jeb Bush then argued about why their proposals for dealing with America’s 11 million undocumented immigrants didn’t constitute “amnesty.” But Trump avoided the subject entirely.

At the second debate, on September 16, CNN’s Jake Tapper tried to make Trump discuss the undocumented already in the country. Tapper quoted Chris Christie as saying that, “There are not enough law enforcement officers—local, county, state, and federal combined—to forcibly deport 11 to 12 million people.” Trump responded that, “First of all, I want to build a wall, a wall that works.” Then he said, “we have a lot of really bad dudes in this country from outside … They go, if I get elected, first day they’re gone. Gangs all over the place. Chicago, Baltimore, no matter where you look.” Tapper then turned to Christie, who discussed the logistical impossibility of deportation. After that, Trump and Jeb Bush sparred about whether Trump has insulted Bush’s Mexican-born wife. Lost in the melee was the fact that Trump had promised only to deport undocumented immigrants who are violent criminals. He had ducked Tapper’s question about the entire 11 million.

Finally, in the third debate, on October 28, CNBC’s John Harwood mentioned that Trump had promised “to build a wall” and “send 11 million people out of the country.” Trump ignored the reference to deporting 11 million and focused his answer on the wall, which, he noted, would be only one-thirteenth as long as the Great Wall of China and would have a “big, fat beautiful door right in the middle.”

It’s not that Trump never discussed deportation during the primaries. Over the course of hundreds of interviews, he was occasionally forced to admit that, yes, he would send all the undocumented home. But he discussed the topic as little as possible, for the same reason he avoided discussions of how to end the civil war in Syria and how to design a conservative replacement for Obamacare: He couldn’t condense his answer into an appealing bumper sticker. For months and months, Trump watched his GOP opponents discuss such topics as he soared above them in the polls. If they, who actually knew something about government, couldn’t spin policy flax into electoral gold, why on earth would he, a policy ignoramus, try?