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5 things you should know about Trump's new national security strategy

President Trump is unveiling his National Security Strategy on Monday. Below are five things you need to know about the new document. (AP Photo/Evan Vucci)

After nearly a year in office, President Trump will unveil his National Security Strategy Monday in a speech at the Ronald Reagan Building in Washington, D.C.

The document, said to run 70 pages, is more than twice as long as the previous strategy document published by the Obama administration in 2015. It is an attempt to flesh out the president’s vision of U.S. foreign policy, which he has shorthanded as “America first.”

Here are five things you should know about the strategy:

What role does the strategy play in shaping policy? Think of the National Security Strategy as a mission statement, one that translates the president’s vision into a series of practical principles that serve as guide to policy decisions on everything from involvement in foreign wars to immigration law. In a recent speech, national security adviser Lt. Gen. H.R. McMaster called it “a dramatic rethinking of American foreign policy from previous decades.”

What are its guiding principles? The full strategy will be released Monday in conjunction with the president’s remarks, but McMaster has already sketched its four pillars in broad terms. They are: Protecting the homeland, advancing American prosperity, preserving peace through strength, and enhancing American influence.

Who wrote it? The NSS is largely a product of the National Security Council, including McMaster, his outgoing deputy Dina Powell, and Nadia Schadlow, a close confidant of McMaster. But the document was fashioned with input from experts inside and outside government, including members of Congress, think tanks, and industry CEOs.

How is it different? Under President Barack Obama, the U.S. focused on the “big 4 plus 1,” which is threats from China, Russia, North Korea, and Iran, plus terrorism. The Trump strategy also names China and Russia as “revisionist powers," and North Korea and Iran as “rogue regimes.” But it also defines the threats in terms of economic competition, not just military strength.

The Trump document calls on America to defend its economic interests with its military, including trade deals and military alliances. And it stresses those alliances must be a two-way street in which allies contribute their fair share and don’t depend on the U.S. to do all the heavy lifting. Think NATO.

Has the U.S. always had a formal NSS? No. The first official National Security Strategy was released in 1987, near the end of the Reagan administration. The Cold War was still going on, and the document was billed as a “radical rethinking” of American foreign policy.

At a speech at the Ronald Reagan presidential library this month, McMaster credited Reagan for ushering in a new era of American confidence, reaching a new height of influence and prosperity. “As we approach the unveiling of President Trump’s national security strategy, we are at a similar crossroads,” McMaster said. The new strategy will help reclaim “America’s strategic confidence," he said.