U.S. President Donald Trump on Sunday announced a 100% tariff on movies produced outside the country, saying the American movie industry was dying a "very fast death" due to the incentives that other countries were offering to lure filmmakers.

The president called the use of incentives by foreign countries to draw filmmakers and studios away from the U.S. a national security threat.

Here are seven major questions left unanswered on Trump’s proposal: Trump only said he was “authorizing” the U.S. Trade Representative and the Commerce Department to impose a 100% tariff on foreign films. He didn’t say he would do it. With previous tariff threats, Trump has sometimes made good and sometimes backed off in the face of pressure.