WASHINGTON, Dec 5 (Reuters) -- The United States will reassert its dominance in the Western Hemisphere, build military strength in the Indo-Pacific, and possibly reassess its relationship with Europe, President Donald Trump said on Friday in a sweeping strategy document that seeks to reframe the country's role in the world. The National Security Strategy, released overnight, described Trump's vision as one of "flexible realism" and argued that the U.S. should revive the 19th century Monroe Doctrine, which declared the Western Hemisphere to be Washington's zone of influence. It also warned that Europe faces "civilizational erasure" and must change course.