(Reuters) - President Donald Trump’s unpredictable foreign policy moves have sent shock waves around the world, from his overhaul of U.S. trade relationships to his questioning of longstanding alliances.

FILE PHOTO: Former Vice President Joe Biden speaks as South Bend Mayor Pete Buttigieg, Senator Bernie Sanders, Senator Elizabeth Warren and Senator Kamala Harris listen during the 2020 Democratic U.S. presidential debate in Houston, Texas, U.S., September 12, 2019. REUTERS/Mike Blake/File Photo

But the Democratic contenders hoping to challenge him in the November 2020 U.S. election have largely eschewed foreign policy debates, seen as less important to U.S. voters, instead focusing on domestic issues such as healthcare, immigration and gun control.

When they have spoken of America’s role in the world, they generally have emphasized an intent to rebuild U.S. alliances damaged by Trump’s “America First” doctrine.

The Democrats are also broadly in agreement on the need to re-enter the Iran nuclear deal that Trump abandoned, to push North Korea to give up its nuclear weapons program, and for a two-state solution for the Israelis and Palestinians.

Differences have emerged on whether to reverse Trump’s tariffs on imports from China, and on when the United States should use military force overseas.

Here is a look at the foreign policy positions of the top 10 Democratic candidates.

JOE BIDEN

The former vice president and Democratic front-runner has said he wants to repair America’s standing in the world and alliances like the North Atlantic Treaty Organization (NATO).

“The next president is going to have to be able to pull the world back together,” Biden told National Public Radio in an interview published on Sept. 3. “Four more years of this president, there will be no NATO,” Biden added.

Biden also said Trump’s call in August for Russia to be invited back into the G7 group of nations was “embarrassing,” adding that the Republican president’s overtures to Russian President Vladimir Putin while spurning traditional U.S. allies were “irrational and self-defeating”.

Biden once told Putin during a meeting, “I don’t think you have a soul,” Biden later said. As vice president, Biden condemned Russia’s 2014 annexation of Crimea.

Like other Democratic candidates, Biden has denounced Russian interference in the 2016 U.S. election. Biden has said he would pursue an extension of the New START nuclear arms control treaty with Russia, which expires in 2021 and which Trump has not committed to extending.

On trade, Biden has indicated he would lift some tariffs that are damaging to U.S. farmers, but said he also would prevent China from stealing intellectual property and “dumping steel on us.”

Biden, who served as Democratic former President Barack Obama’s vice president for eight years, has argued he has the foreign policy experience that none of the other Democratic candidates possess. Obama trusted Biden with withdrawing troops from Iraq and uniting allies to combat Islamist terrorism, Biden said in his NPR interview.

But his long record also opens Biden up to criticism. He voted in 2002 to authorize the use of military force against Iraq, paving the way for President George W. Bush’s 2003 invasion that led to a long and costly conflict and destabilized the Middle East.

Biden later called his vote a mistake and has promised to end America’s “forever wars.” In a Democratic debate in Houston this month, he said he would withdraw U.S. forces from Afghanistan and suggested using bases in Pakistan to “prevent the United States being the victim of terror coming out of Afghanistan.”

BERNIE SANDERS

The U.S. senator from Vermont has combined his calls for a “political revolution” at home with a vision for a shift in U.S. policy overseas. Sanders has criticized high levels of military spending that enrich defense contractors and pledged to cool tensions with Iran.

Sanders said in this month’s debate that he and Biden strongly disagree on trade, citing his opposition to trade deals like the North American Free Trade Agreement that Sanders said led to job losses.

In the past, Sanders expressed solidarity with left-wing governments, but now draws a distinction between his avowed “democratic socialism” and governments like that of Venezuela’s Nicolas Maduro, who he has called a “vicious tyrant.”

As well as opposing Cold War-era policies, he voted against the Iraq war and co-authored a bipartisan resolution to try to end U.S. involvement in the Saudi Arabia-led war against Houthi insurgents in Yemen.

ELIZABETH WARREN

The U.S. senator from Massachusetts has pledged to create a foreign policy with a focus on creating and defending jobs in the United States. Warren has said she would cut the “bloated defense budget.”

“We need to bring our troops home” from Afghanistan, Warren said in a Democratic debate, “and then we need to make a big shift. We cannot ask our military to keep solving problems that cannot be solved militarily.”

Warren was the first major candidate to call for Trump to be impeached for taking actions to impede the federal investigations of Russian election interference. She also criticized the president’s June meeting with Putin in which Trump appeared to make light of the election interference.

PETE BUTTIGIEG

Buttigieg studied abroad in England and Tunisia and worked for the global consulting firm McKinsey & Company. He took time out of his first term as mayor of South Bend, Indiana to deploy to Afghanistan with the U.S. Navy Reserve.

Buttigieg has pledged to reverse two pivotal steps taken by Trump by having the United States rejoin the Iran nuclear deal and Paris climate accord. Buttigieg has argued for scrapping the authorization for use of military force passed by Congress in the wake of the Sept. 11, 2001, attacks on the United States, saying it has become a “blank check” for the use of force.

“When America acts alone, it can only be because core interests are at stake and because there is no alternative,” said Buttigieg, adding that neither the situation in Venezuela nor that in Iran passed that test. He also has said he would withhold U.S. funds from Israel if it annexes West Bank settlements.

KAMALA HARRIS

The U.S. senator from California has not issued a detailed foreign policy plan, but has emphasized restoring America’s traditional alliances like NATO. She has said trade policy should help the United States “export American products, not American jobs,” but added the nation needs to trade with the world and should partner with China on climate change issues and North Korea. “I am not a protectionist Democrat,” Harris said.

Harris has been criticized by some on the left for her links to the American Israel Public Affairs Committee (AIPAC), a pro-Israeli lobbying group. Her website describes her support for Israel as “unshakeable” and that she would “work towards a two-state solution so that Palestinians and Israelis can govern themselves in security, dignity and peace.”

ANDREW YANG

Along with his flagship domestic proposal for a universal basic income for all Americans over age 18, Yang has proposed a “reverse boot camp” to ensure military service members are ready to return to civilian life. The former tech entrepreneur’s foreign policy initiatives include a proposal to develop new encryption standards that are not vulnerable to quantum computing technology, as well as to invest in quantum technology to stay ahead of geopolitical rivals.

Yang also has said the decision to launch a nuclear attack should not rest solely with the president, proposing that the vice president also verify such calls.

CORY BOOKER

The U.S. senator from New Jersey has criticized Trump’s foreign policy as an “America alone policy” and emphasized working with allies to take on the challenges of China and climate change.

“We are the strongest nation on the planet Earth, and our strength is multiplied and magnified when we stand with our allies in common cause and common purpose,” Booker said in a debate. “That’s how we beat China.”

Booker has said it was a mistake for Trump to pull out of the Iran nuclear deal but that he would take the opportunity to renegotiate the agreement.

BETO O’ROURKE

The former U.S. congressman from Texas has said he would end Trump’s trade war on day one of his administration and suspend tariffs, a commitment none of the other top 10 Democratic candidates have made. O’Rourke has proposed leading a global coalition to pressure China to end anti-competitive behavior.

JULIAN CASTRO

The former U.S. secretary of Housing and Urban Development said in a debate he would put a renewed focus on Latin America to address immigration and to compete with China’s growing influence there.

He said a “21st Century Marshall Plan for Central America,” like the post-World War Two initiative to rebuild Western Europe, is needed “so that people can find safety and opportunity at home instead of having to make the dangerous journey to the United States.”

The United States should also pressure Venezuela to have free and fair elections and offer those fleeing the country temporary protected status, Castro said.

TULSI GABBARD

The U.S. congresswoman from Hawaii has made her anti-war position central to her campaign. Gabbard, an Iraq war veteran, has spoken against U.S. involvement in Syria’s civil war as part of a personal campaign to end “regime change wars.” She has met with Syrian President Bashar al-Assad and expressed skepticism that his government was behind chemical weapons attacks, drawing fierce criticism from some in her own party.