President Trump has signed off on the core elements of the National Security Strategy (NSS). The draft is almost completed, and all the principals — James Mattis, Rex Tillerson, Steven Mnuchin, etc. — have agreed on its core components. The document will be rolled out soon.

Why this matters: The NSS is as important as strategy documents get. It will explain how Trump's "America First" mantra applies to the vast range of threats America faces, including Chinese economic competition, Russian influence operations, and the weaponization of space. It's designed to guide the Trump administration's foreign policy and national security decisions, according to three sources familiar with it.

Behind the scenes: Nadia Schadlow, a well-respected member of the National Security Council and trusted confidant of H.R. McMaster, spent months drafting the document, working with Deputy National Security Adviser Dina Powell and McMaster.

Schadlow and Powell met with dozens of members of Congress, cybersecurity and foreign policy experts, military strategists and CEOs.

The big players across the agencies — including Mike Pompeo, Dan Coats, Jeff Sessions, Gen. Mattis, Wilbur Ross, Mnuchin, Tillerson, and, naturally, McMaster — all support the strategy.

They'll review the document this week at their cabinet meeting.

What's different: Sources familiar with the document call it "hard-nosed" and "realistic" — and less ambitious and idealistic than prior efforts. Critics will likely argue it forfeits American values and moral leadership — a continuation of Trump's lack of interest in fighting climate change and spreading democracy, his exit from the Paris climate deal and the Pacific trade deal.

Sources described the Trump NSS as a "corrective" to the past 16 years of American foreign policy, that overestimated America's influence and importance, and lost track of priorities. Trump's document won't do any of those things, the sources said.

I haven't seen the Trump NSS, which remains under close hold. But sources familiar with it tell me to expect three things:

"There is more focus on homeland security and protecting the homeland than any NSS before," said one source with knowledge of the document. The strategy will focus on economic competitiveness as a national security imperative, especially regarding China. That fits into Trump's long-held belief that foreign countries have been taking advantage of America and stealing U.S. jobs. The document will highlight the emergence of technological threats, including — per Newt Gingrich, who has worked with Schadlow and Powell to draft the document — Russia's hybrid warfare and new breakthroughs in the weaponization of space.

Looking ahead: Jeremy Bash — formerly Leon Panetta's chief of staff at the CIA and Defense Department — told me it's unusual for a White House to complete the NSS in its first year, and said Powell and Schadlow deserve credit for building consensus so quickly. But he added it will only be useful if tethered to achievable goals. "The hard part begins now," he said.