Foreign and defense policy
In the Senate, Kaine has supported the normalization of U.S.–Cuban relations and the international nuclear agreement with Iran.
Kaine expressed support for Israel's right to defend itself during the 2014 Gaza War. In September 2016, in advance of a UN Security Council resolution 2334 condemning Israeli settlements in the occupied Palestinian territories, he signed an AIPAC-sponsored letter urging Obama to veto "one-sided" resolutions against Israel.
In 2015, Kaine expressed support for the Saudi-led coalition's airstrikes in Yemen against Houthi forces fighting the government of President Abdrabbuh Mansur Hadi, but in 2018, he was one of seven senators to sign a letter to Secretary of State Mike Pompeo saying that they found it "difficult to reconcile known facts with at least two" of the Trump administration's certifications that Saudi Arabia and the United Arab Emirates were attempting to protect Yemeni civilians and were in compliance with U.S. laws on arms sales, citing an inconsistency with a memo from Pompeo to Congress expressly stating that on some occasions the Saudi and Emirates governments had failed to adopt measures to reduce civilian casualties. Kaine also condemned the Trump administration for its "eagerness to give the Saudis anything they want" after the administration approved the transfer of nuclear technology to Saudi Arabia after the murder of Saudi dissident Jamal Khashoggi.
In July 2017, Kaine voted for the Countering America's Adversaries Through Sanctions Act that placed sanctions on Iran, Russia, and North Korea.
In 2019, Kaine was one of 34 Senate Democrats to sign a letter to Trump urging him to reconsider cuts to U.S. foreign aid to the Northern Triangle countries of Central America in the Fiscal Year 2018 national security appropriations bill. The letter said that Trump had "consistently expressed a flawed understanding of U.S. foreign assistance", viewing it as a gift or charity to foreign governments rather than a tool to promote American interests and collective security. The senators wrote that U.S. foreign assistance to Central American countries, by improving stability and alleviating poverty in the region, reduced Central American migration flows to the U.S.
In 2019, Kaine co-sponsored the South China Sea and East China Sea Sanctions Act, a bipartisan bill reintroduced by Marco Rubio and Ben Cardin that was intended to disrupt China's consolidation or expansion of its claims of jurisdiction over both the sea and airspace in disputed zones in the South China Sea.
In 2023, Kaine and Rubio co-sponsored a provision in the annual National Defense Authorization Act that a U.S. president cannot withdraw the U.S. from NATO without Congress's approval.
On December 30, 2023, Kaine criticized Biden's emergency sale of weapons to Israel during the Gaza war, stating, "Why should the Admin bypass Congress on arms sales to any nation? Bypassing Congress = keeping the American public in the dark." Some of Biden's closest allies in the Senate, including Kaine, were reportedly pressuring Biden to change his tactics in Gaza.
In 2024, Kaine expressed his support for an independent Palestine, saying, "Since Israel has made plain that it will not accept Palestinian autonomy, the U.S. should no longer condition recognition on Israeli assent, but instead upon Palestinian willingness to peacefully coexist with its neighbors." In November 2024, Kaine was one of 19 senators to vote to block the United States' arms sales to Israel.
After the 2016 presidential campaign, Kaine wrote an extensive essay in Foreign Affairs outlining his underlying foreign policy philosophy. According to Kaine, American foreign policy has suffered a lack of direction since the 1990s because the end of the Cold War rendered irrelevant America's previous grand strategy, which he identifies as the Truman Doctrine. This lack of grand strategy makes American actions seem random, complicating the policy-making process and hindering American leaders' efforts to convince the public that American foreign policy is worthwhile. To remedy this, Kaine proposed a new grand strategy based mainly on democracy promotion. His grand strategy is informed by a tri-polar balance of international power, with one pole being democratic states including the U.S. and its allies, the second autocratic powers led by Russia and China, and the third nonstate actors (multinational corporations, NGOs, gangs, etc.).
First, Kaine believes that the United States should work to support democracy in already democratic countries, as democracy globally has been declining for many years. To maintain democracy in democratic countries, Kaine proposes the creation of an intergovernmental organization consisting of all the world's democracies in which states can cooperate on solutions to problems such as corruption and voter inclusion. He compares this hypothetical group to the Organization for Economic Cooperation and Development, in which advanced industrialized countries collaborate on economic policy. Kaine believes that this new organization will help democracies remain democratic, as well as promote democracy in other countries by giving them viable democratic examples to emulate. In this way, Kaine says that the U.S. should no longer see itself as the indispensable nation, but rather the "exemplary democracy".
Second, Kaine proposes that democracies should coordinate to best interact with authoritarian states. Depending on the circumstances, democracies should either "confront", "compete", or "cooperate" with autocracies. For example, Kaine observes that the U.S. competes with its authoritarian adversaries by strengthening military and commercial alliances, and confronts them by decrying their human rights records.
Finally, Kaine believes that democracies and autocracies should cooperate when they have the same interests, such as combating climate change.
In July 2017, Kaine expanded on the grand strategy proposed in this essay in an interview at the Brookings Institution with international relations scholar Robert Kagan.
Kaine's website states, "The main mission in Afghanistan—destroying Al Qaeda—is nearly complete and we should bring our troops home as quickly as we can, consistent with the need to make sure that Afghanistan poses no danger in the broader region."
Kaine believes that American foreign policy has neglected relations with Latin America and argues for an increased focus on the Americas, saying, "We have seldom paid enough attention to the Americas, in particular, and when we have—whether through the Monroe Doctrine or by battling communist movements during the Cold War—we have focused more on blocking outsiders from building influence in the Western Hemisphere than we have on the nations already there."
Kaine is known for "expertise on the constitutional powers of the presidency" and has said that "war powers questions" are a "personal obsession" of his. He has stressed that under the Constitution, "Congress has the power to declare war—and only Congress." Kaine called the 2018 U.S. missile strikes Trump ordered against the Syrian government illegal because they were undertaken without congressional approval.
Kaine and Senator John McCain introduced the War Powers Consultation Act of 2014, which would replace the War Powers Act of 1973, bringing Congress back into decisions on the deployment of U.S. military forces. The bill would establish a Congressional Consultation Committee, with which the president would be required to consult regularly regarding significant foreign policy matters before ordering the deployment of the armed forces into a significant armed conflict and at least every two months for the duration of any significant armed conflict. Kaine argued for the bill by citing his "frustration" over the sloppiness of "process and communication over decisions of war", noting that "presidents tend to overreach and Congress sometimes willingly ducks tough votes and decisions. We all have to do better."
In February 2018, Kaine was one of 18 senators to sign a letter to Trump arguing that striking North Korea with "a preventative or preemptive U.S. military strike would lack either a constitutional basis or legal authority" without congressional approval.
In January 2020, Kaine introduced a new war powers resolution that would prohibit the U.S. from entering hostilities against Iran within 30 days unless it was responding to an imminent threat. The next month, the Iran War Powers Resolution passed the Senate 55–45, securing the votes of eight Republicans along with the Democrats. Trump vetoed the measure, and the Senate failed to override the veto.
In December 2025, Kaine sponsored S.J. Res. 98, "A joint resolution to direct the removal of United States Armed Forces from hostilities within or against Venezuela that have not been authorized by Congress". In January 2026, it advanced to a floor vote in the Senate.
In 2014, Kaine argued that the U.S. military intervention against Islamic State of Iraq and the Levant (ISIL) undertaken by Obama was unconstitutional without a new congressional authorization for the use of military force against ISIL. In November 2014, at the Halifax International Security Forum, Kaine and McCain emphasized the necessity of such a congressional authorization, saying: "You just can't have a war without Congress. You can't ask people to risk their lives, risk getting killed, seeing other folks getting killed or injured if Congress isn't willing to do the job to put their thumbprint on this and say, this is a national mission and worth it." After the April 2017 Shayrat missile strike in Syria, ordered by Trump, Kaine said, "There is no legal justification for this. He should not have done this without coming to Congress." On Meet the Press, Kaine said, "I'm a strong supporter that the U.S. should take action to protect humanitarian causes, like the ban on chemical weapons. Where I differ from this administration, and I took the same position with respect to President Obama, we are a nation that's not supposed to take military action, start war, without a plan that's presented to and approved by Congress."
On December 11, 2014, after a five-month campaign by Kaine, the U.S. Senate Foreign Relations Committee approved by 10–8 (along party lines) a measure authorizing military force against ISIL but barring the use of ground troops. In October 2015, Kaine criticized Obama's approach to the Syrian Civil War, saying that the establishment of humanitarian no-fly zones would have alleviated the humanitarian crisis in Syria.
In April 2018, Kaine criticized Trump for authorizing the launch of a precision military strike on Syria without consulting Congress, calling the strike an "illegal military act". In February 2021, Kaine demanded answers from President Biden after he ordered airstrikes on Syria against Iran-backed militias without giving "legal justification" to members of Congress beforehand.
In 2023, Kaine and Todd Young co-sponsored legislation to end 1991 and 2002 congressional resolutions that authorized the use of military force. The bill repealed the Authorization for Use of Military Force (AUMF) in Iraq and passed with a bipartisan majority.
