President Trump blamed his predecessors on Monday for gradually surrendering U.S. sovereignty "to foreign bureaucrats" and failing to keep Americans safe, announcing in a major national security speech that his administration will root its foreign policy in “principled realism" going forward.

"To seize the opportunities of the future, we must first understand the failures of the past," Trump told supporters during remarks at the Ronald Reagan Building in Washington.

Citing former President Barack Obama’s “incomprehensibly bad” nuclear deal with Iran and “disastrous” multilateral trade agreements, Trump accused previous American leaders of forgetting “whose voices they were supposed to respect and whose interests they were supposed to defend."

“Last year, all of that began to change,” he said. “The American people rejected the failures of the past. You discovered your voice and reclaimed ownership of this nation and its destiny.”

Read Trump's 'America First' national security strategy

Much like the foreign policy speeches he gave during his presidential run, Trump blasted his most recent predecessors for engaging in nation-building “while they failed to build up our nation at home.” And he cast the Obama administration’s lax immigration policies as a major threat to the safety of the American people.

"Our leaders drifted from American principles," Trump declared. "They lost sight of America's destiny, and they lost their belief in America's greatness."

The president said his national security strategy will help advance America’s influence around the globe by confronting “revisionist” powers like China and Russia, who seek to undermine the U.S. and disrupt international peace.

Such nations “want to shape a world antithetical to U.S. values and interests,” according to a strategy document released just ahead of the president’s remarks.

Related: 'America is coming back': Trump says new national security strategy heralds the nation's resurgence

Trump urged Americans on Monday to “take their part” in protecting themselves and their neighbors and restoring U.S. dominance.

“Every American has a role to play in this grand national effort,” he said. “Together, our task is to strengthen our families, build up our communities, and to celebrate American greatness as a shining example to the world.”