Bloomington, Indiana (CNN) In a 2020 Democratic primary race dominated by expansive domestic policy proposals , South Bend, Indiana, Mayor Pete Buttigieg sought on Tuesday to lay down a marker of his own on a different front: Foreign policy.

Buttigieg, the 37-year-old former naval inWtelligence officer, pledged as president to rejoin the Iran nuclear deal, view -- and act -- on climate change as a national security issue and reset the US posture on foreign entanglements that has grown more expansive -- with limited congressional input -- in the nearly 19 years since the 9/11 terrorist attacks.

"As the mission drifted, the collateral damage to our national moral authority was enormous, and we too often bargained against our own values," Buttigieg said in a wide-ranging speech here. "Congress abdicated its responsibility on issues of war and peace."

While several candidates in the 2020 field have delved into the topic in spurts, Buttigieg's lengthy foray into the foreign policy arena signals an effort to stake a claim on an issue repeatedly elevated to the forefront of the national conversation by President Donald Trump. In a speech that aides said had been in the works for weeks -- and would consciously serve to separate Buttigieg from the field -- he framed the need for a shift from the Trump administration's strategy as "urgent."

"We need a strategy," Buttigieg said. "Not just to deal with individual threats, rivalries, and opportunities, but to manage global trends that will define the balance of this half-century in which my generation will live the majority of our lives."

But Buttigieg extended his critique beyond Trump -- one that could implicitly be viewed as a shot at current Democratic front-runner Joe Biden -- noting that "for the better part of my lifetime, it has been difficult to identify a consistent foreign policy in the Democratic Party either."

Buttigieg said Tuesday that his speech -- perhaps the lengthiest of his campaign -- is not an effort "to deliver a full Buttigieg doctrine," but instead to lay out why "the world today needs America more than ever, but only if America can be at her best."

Buttigieg has assembled a volunteer team of more than 250 foreign policy experts, according to Doug Wilson, the former assistant secretary of Defense under President Barack Obama. Wilson is leading the group, which includes Tarek Ghani, a Washington University assistant professor, and Ned Price, a former National Security Council special assistant under Obama.

"There was a process of discussing what major things he wanted to accomplish and what he wanted to articulate," Wilson said. "He very much did not want to do a check-the-box, laundry list speech and he wanted to talk about what you wanted to know in order to build foreign policy over the long term."

Wilson added that the "speech was written virtually entirely by" the mayor.

For Buttigieg, who served a tour in Afghanistan, foreign policy is an area he has increasingly touched on from a 30,000-foot level since his entrance into the race, often citing his personal experience as bona fides for a generational shift in how the US approaches its role in the world.

But his speech marked the most concentrated effort yet to lay out tenets of a foreign policy platform. It was designed to lay claim to an issue that has received less attention than big picture domestic policy pushes in the race while also seeking to alleviate concerns that his age and lack of national experience would leave him at a disadvantage in a field packed with sitting senators, congressmen and governors.

Echoing an issue he's repeatedly mentioned on the campaign trail, Buttigieg focused heavily on repealing the Authorization for Use of Military Force enacted in 2001, which today stands as the legal rationale for troop deployments in at least 10 locations around the world, including Syria and Iraq.

"Correcting this is not only a matter of presidential restraint but of renewed congressional oversight," Buttigieg said.

The authorization -- and its role as the elastic legal basis for deployments around the world -- has for years served as a hot button issue on Capitol Hill, where lawmakers have sought, and failed, to scale it back. The Obama administration also proposed a replacement, but it went nowhere on Capitol Hill, where lawmakers have been wary of restricting the administration's authority amid global terror threats.

"The time has come for Congress to repeal and replace that blank check on the use of force and ensure a robust debate on any future operations," Buttigieg said. "We should never again send troops into conflict without a clear definition of their mission and an understanding of what comes after."

He added: "If members of our military can find the courage to deploy to a war zone, our members of Congress ought to be able to summon the courage to take tough votes on war and peace."

Buttigieg said he believes in using force "only ... when left with no alternative" and called on the United States to "end to endless war and refocus on future threats."

The mayor called for "an exceedingly high bar" on the unilateral use of force, noting that strife in Venezuela and Iran do not meet that bar, despite the fact that the Trump administration has threatened use of force against both nations.

"It is the difference between the necessary response to 9/11 in Afghanistan, and the self-defeating invasion of Iraq," Buttigieg said. "It is, in short, the difference between Normandy and Saigon."

He said a Buttigieg presidency would "promote American values by working to reverse the rise of authoritarianism abroad," "must treat climate change as the existential challenge that it is" and "update the institutions for which we engage the world."

Referencing the hot-and-cold relationship between Trump and North Korean leader Kim Jong Un, Buttigieg said Americans would "not see me exchanging love letters on White House letterhead with a brutal dictator who starves his own people."

"But," he added, "you will see my administration work to create the conditions that would make it possible to welcome North Korea into the international community."

In order to do that, however, Buttigieg said sanctions against North Korea would need to remain in place.

The mayor's speech was filled with subtle -- and some not so subtle -- knocks against Trump.

"We don't need a wall from sea to shining sea," the mayor said, knocking Trump's focus on a wall at the US-Mexico border. But Buttigieg also slammed the President's attacks on the press and Trump's handing of the Israel-Palestinian relationship.

The mayor also waded into accusations of anti-Semitism against Americans who criticize Israel and Prime Minister Benjamin Netanyahu, saying that just as a patriot in the United States can knock Trump, "a supporter of Israel may oppose the policies of the Israeli right-wing government."

The candidate also said that a Buttigieg presidency would oppose the annexation of West Bank settlements -- "a President Buttigieg would take steps to make sure that American taxpayers won't help foot the bill," he said -- and warned that if nothing changes in the Israel-Palestine relationship, the two sides "well before 2050... will come to see either peace or catastrophe."

Buttigieg told CNN after his speech that his comments about settlements were "in the context of our relationship" with Israel and were meant to show he is "only going to support steps that are conducive to peace." The United States, he said, needs to do "more than just watch on the sidelines" because "we have to make sure our policies are consistent with our words."

Buttigieg's speech was sprinkled with a number of lines he often uses on the campaign trial, like when the mayor said Democrats should not promise normalcy or the ability to go back to the way things were in the 2000s or the 1990s. The line is often seen as a criticism of Biden, who was a decade into his Senate career when Buttigieg was born.

And the mayor spent time focusing on domestic issues, too, and the way they impact America's standing in the world.

"Our legitimacy abroad rest on our democracy at home," Buttigieg said, pivoting to his campaign pitch to revamp American democracy by doing away with the electoral college.

The mayor also outlined his plan to push a carbon tax and dividend plans and an increase in research and development of green technology.

And on terrorism, Buttigieg said, "In the past decade, more Americans have been killed in America by right wing extremists than by those by al Qaeda or ISIS," before calling for redirecting resources "to combat right wing extremism and violent white nationalism."

Buttigieg closed the speech by trumpeting the importance of the United States, but a certain version of America.

"The world needs America. But not just any America," he said. "Not an America that has reduced itself to just one more player, scrapping its way through an amoral worldwide scrum for narrow advantage. It has to be America at our best... It has to be an America that knows how to make better the everyday life of its citizens and that of people around the world, knowing how much one has to do with the other."