New Zealand is planning to eradicate millions of invasive animals that prey on the country's rare birds. The goal may not be possible, unless new technology can be developed to do it.

The president signed an order earlier this week to send Tennessee state National Guard troops, along with officials from various federal departments and agencies, into Memphis, in an effort to fight crime. It's one of several U.S. cities Trump has singled out for such a move, testing the limits of presidential power and military force.