Venting his frustration with immigration earlier this year, President Trump suggested that U.S. soldiers patrolling the southern border shoot migrants in the legs to slow them down, put flesh-piercing spikes atop an electrified border wall and dig a moat.
 And fill the moat with snakes and alligators.
 That’s according to an excerpt from a new book, “Border Wars: Inside Trump’s Assault on Immigration,” by New York Times reporters Michael D. Shear and Julie Hirschfeld Davis, due out next week. The Times published the excerpt on Tuesday.
 Trump floated the man-eating moat idea in March — and advisers reportedly took it seriously enough to “seek a cost estimate.”
 It wasn’t the only extreme solution offered by Trump, according to the excerpt:
 He wanted the wall electrified, with spikes on top that could pierce human flesh. After publicly suggesting that soldiers shoot migrants if they threw rocks, the president backed off when his staff told him that was illegal. But later in a meeting, aides recalled, he suggested that they shoot migrants in the legs to slow them down. That’s not allowed either, they told him.

 Trump denied part of the report in a tweet in which he misspelled “moat.”