On some issues, the most popular position in the one smack-dab in the middle. This is true for the environment, and for gay rights. But on most issues, the “center” of public opinion is often off-center — sometimes substantially so.
On marijuana, the single most popular position was full legalization. On immigration, it was “the immediate roundup and deportation of all undocumented immigrants and an outright moratorium on all immigration until the border is proven secure.”
These are the kinds of voters Trump could appeal to: voters who hold a basket of opinions that aren’t quite represented by either party. Voters who want to deport all unauthorized immigrants while also spending more money on Social Security, or voters who are skeptical of free-trade agreements even as they’re virulently anti-abortion.