Trump threatens to block Mexican immigrants from sending money to their families if Mexico doesn’t pay for the wall

In a two-page memo provided to the Washington Post, Donald Trump has finally elaborated on how he would make Mexico pay for the border wall even if the nation refuses. He’d present two options: “Make a one-time payment of $5-10 billion” or he’ll halt remittances sent back home by Mexican immigrants living in the U.S. (an estimated $24 billion). Is that even legal?