President Trump offered an unexpected twist in his trade wars Sunday evening by floating a 100% tariff on foreign movies, but he did it in a familiar way by hinting that a national emergency declaration could be in the offing to achieve his ends.

"This is a concerted effort by other Nations and, therefore, a National Security threat," he posted on Truth Social. He later added to reporters that part of his issue is other countries offering incentives for movie production, "so that's sort of a threat to our country in a sense."

Trump has used similar language before other formal declarations. His focus on emergency action is a strategy that his team has closely studied for years to help him move quickly and bypass Congress.

It is also still possible that the Hollywood action does not become an emergency. Trump has discussed emergencies but declined to follow through in some cases.

If he does in fact do so with Hollywood, it would follow eight formal national emergencies that Trump has already declared since taking office, according to the Brennan Center for Justice.

Those proclamations span a wide array of issues from energy to the border to, most notably, his "Liberation Day" reciprocal tariffs.

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Trump also uses emergency language relentlessly, even if it's not backed up by formal action. He posted in January about redirecting water in California "under Emergency Powers" in claims that were refuted by California's government.

A way for Trump to focus on both California and Canada

Details remain scarce about what he intends to do with movies. 

The White House declined to offer any formal plans in the hours after his pronouncement beyond Trump's message that he was authorizing the Department of Commerce and his trade representative to "begin the process of instituting a 100% Tariff on any and all Movies coming into our Country that are produced in Foreign Lands."

It's unclear if any order would apply to television as well or what exactly constitutes a movie being produced overseas.

The move was nevertheless quickly felt, with shares in companies like Netflix (NFLX), Warner Bros. Discovery (WBD), and Walt Disney (DIS) all lower in early trading Monday.

Trump's focus on Hollywood is also a factor in two contentious personal relationships that have been front and center in recent weeks.

Canada is a key destination for Hollywood film and television productions (with the nation indeed offering generous incentives), and Trump’s post comes as the president is set to meet Canadian Prime Minister Mark Carney at the White House on Tuesday.

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It's also just the latest in a long-running feud with California Governor Gavin Newsom.

Trump again slammed Newsom in Sunday evening's comments to reporters, calling the California governor "grossly incompetent" while downplaying the Canadian connection slightly by saying "Canada is only one of many countries" that he sees as threatening Hollywood.

A flurry of national emergencies

Trump is far from the only president to invoke national emergencies, a feature of the US political landscape since the National Emergencies Act of 1976, but he has stretched those powers to new heights.

Over the years, according to the Brennan Center, 88 national emergencies have been invoked. And dozens remain technically in force from previous years.

Trump has gone further and invoked three emergencies on his first day in office. He has also claimed sweeping powers with his "Liberation Day" tariffs by declaring a national economic emergency using a 1977 law called the International Emergency Economic Powers Act.

It's power that has allowed Trump to enact 10% tariffs on nearly the entire world and bring in billions in revenue. Additional duties are currently paused but a summer deadline looms.

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The president also said this weekend that free trade deals could be in the offing but repeatedly added that he views his tariff authority — derived from that emergency declaration — as one that gives him nearly limitless latitude.

"We're negotiating with many countries, but at the end of this I'll set my own deals," he said Sunday, adding that news on that front could be coming "at some point in the next two weeks or three weeks."

It's an approach from Trump that has raised an array of legal issues, with Newsom at the center of the pushback and currently leading a lawsuit to strip Trump of his emergency tariff powers.

"The President of the United States simply does not have the legal authority under the Emergency Economic Powers Act to impose tariffs. Period." Newsom offered in a recent television appearance.

Newsom's case is that vagueness in the 1977 law doesn't directly allow a president to use tariffs as a means to combat an emergency.

Newsom, who is also pushing a plan to increase California's film and TV tax incentives, didn't immediately respond to Trump's latest push.

But the Governor's senior communications adviser offered a similar message to Deadline, saying of possible Hollywood tariffs, "We believe he has no authority to impose tariffs under the International Economic Emergency Powers Act, since tariffs are not listed as a remedy under that law."

Ben Werschkul is a Washington correspondent for Yahoo Finance.

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