text: Armies, Corps, and Divisions
  lower echelons maneuver forces (JP 3-0). Engagements are typically conducted at brigade level and below.
  They are usually short, executed in terms of minutes, hours, or days.
  1-15. In large-scale combat operations, corps headquarters normally function as a tactical land headquarters
  under a joint or multi-national land component. The corps headquarters is organized, trained, and equipped
  to control the operation of two to five divisions, together with supporting organizations (see Chapter 4).
  Divisions are the tactical units of execution for a corps. The division headquarters’ primary role is a tactical
  headquarters controlling two to five brigade combat teams (BCTs) and two to four functional and
  multifunctional brigades in decisive action. The distinguishing difference between corps and division tactical
  operations are their scope and scale. (See chapters 4 and 5 for more information on corps and division
  operations.)
  1-16. It is important to understand tactics within the context of the levels of warfare. The strategic and
  operational levels provide the context for tactical operations. Without this context, tactical operations are
  reduced to a series of disconnected and unfocused actions. Strategic and operational success is a measure of
  how one or more battles contribute to winning a major operation or campaign. (See ADP 3-90 for more
  information on tactical doctrine.)
  GLOBAL OPERATIONAL ENVIRONMENT
  1-17. The United States faces a strategic environment characterized by the reemergence of long-term
  competition with peer and near-peer threats bent on challenging American leadership and remaking the global
  order in their favor. This increasingly complex global security environment is a result of increasing long-
  term competition between nations, the rapid diffusion of new technologies, and the increased movement of
  people across borders. Combined, these factors challenge the international order and provide opportunities
  for state and non-state actors to leverage them to their advantage.
  1-18. Broad trends like globalization, urbanization, technological advances, and failing states affect land
  operations. These trends create instability and contribute to an environment of persistent competition that
  encompasses competition below armed conflict, periodic crisis, and episodic armed conflict. Competition is
  a fundamental part of international relations, as state and non-state actors seek to protect and advance their
  own interests. These actors sometimes cooperate, but more often they compete for strategic advantages.
  Adversaries to U.S. interests employ capabilities that counter U.S. interests and impede friendly operations
  while advancing their own interests.
  1-19. Adversaries often coordinate their actions across all four instruments of national power to create
  conditions that challenge U.S. interests. Peer threats, including China and Russia, along with the rogue states
  of North Korea and Iran, operate across the competition continuum to achieve their objectives. China and
  Russia seek regional dominance by creating conditions advantageous to their objectives, largely at the
  expense of neighboring countries. Chinese expansionist policies threaten U.S. partners, allies, and interests.
  Recent Russian efforts meld military action and information warfare with coordinated diplomatic and
  economic efforts to intimidate their neighbors and threaten the North Atlantic Treaty Organization (NATO)
  and allied partners. North Korea and Iran actively seek to coerce their neighbors in order to advance their
  interests and stabilize their governments.
  1-20. Rapid technological advances and the diffusion of technology present another threat. U.S. forces no
  longer enjoy uncontested access across all domains. Chinese and Russian forces are increasingly capable of
  challenging U.S. forces across all domains, while North Korean and Iranian forces are capable of creating
  periods of overmatch in critical domains during competition and large-scale ground combat. China and
  Russia already possess nuclear arsenals, while North Korea and Iran are actively seeking to develop their
  own in an effort to offset U.S. and allied advantages. The proliferation of information technology allows U.S.
  adversaries to exploit opportunities through robust information warfare campaigns designed to discredit
  friendly action and subvert popular support at home and abroad.