Americans Largely Support Using US Troops to Defend Allies

The public also remains in favor of maintaining long-term military bases abroad.

The US alliance system has been a pillar of US foreign relations over the past 70 years. But with the advent of former President Donald Trump as the leader of the Republican Party, there are now serious discussions about the US commitment to allies, the cost the United States pays to maintain such a system, and its effectiveness moving forward. While Americans overall see security alliances as beneficial to the United States, a significant portion of Republicans say these alliances mostly benefit US allies. Even so, Americans across the board remain supportive of maintaining long-term military bases abroad—a core component of the US alliance system.

Key Findings

• A majority of all Americans (64%) say alliances either benefit the United States and its allies (51%) or mostly benefit the United States (13%).
• Republicans are more divided, with 39% saying alliances mostly benefit US allies versus 45 percent who think alliances benefit the United States and its allies.
• While Americans support the use of US troops to defend allies in specific scenarios, there is hesitance to engage China in a conflict. Just 44 percent say US troops should be used if China initiates a military conflict with Japan over disputed islands and 43 percent support the use of US troops if China invaded Taiwan.

Security Alliances Seen as Beneficial

When it comes to views on security alliances, the American public is broadly positive on their benefits. Nearly two in three (64%) say security alliances either benefit both the United States and its allies (51%) or mostly benefit the United States (13%). However, there are significant gaps between Republicans and Democrats. While a majority of Democrats (58%) see alliances as mutually beneficial, only 45 percent of Republicans say the same. Moreover, 39 percent of Republicans versus 19 percent of Democrats see alliances as one-sided, with those benefits accruing mostly to US allies.

This rise in views of alliances as one-sided is likely driven by Republican leadership messaging about the costs of alliances, especially in light of ongoing US support for Ukraine in the face of the Russian invasion. Moreover, both as president and as a candidate, Trump has accused Japan, South Korea, and NATO of free-riding as they underspend on their own defense.

Bipartisan Support for US Military Bases Abroad

Even as a greater portion of Republicans question the benefits of US alliances, this does not seem to dampen their support of US military bases abroad—a defining feature of the US alliance system. This is likely tied to the importance Republicans place on the physical defense of the United States and military bases abroad being an important component in that defense. But it is not only Republicans that support US military bases abroad. Democrats also support most long-term military bases abroad with few exceptions. The two most notable: Australia, where 48 percent support long-term bases, and Turkey, where that number is 46 percent.

American Public is Discerning When Using US Troops Abroad

Maintaining US alliances and military bases abroad comes with the inherent chance that at some point the troops stationed on those bases will be involved in a conflict. This is mandated by the defense treaties the United States has signed and the credibility of that promise forms the backbone of the US alliance system. Overall, the American public is supportive of using US troops when an official ally is involved. This includes if Russia invaded a NATO ally like Germany (65%), if Russia invaded a NATO ally like Latvia, Lithuania, or Estonia (54%), or if North Korea invaded South Korea (51%). There is one notable exception, however. If China initiates a military conflict with Japan over disputed islands, a minority of Americans (44%) support the use of US troops.

It is also noteworthy that only minorities support the use of US troops if a non-official ally is involved in the conflict scenario. If China invaded Taiwan, 43 percent of Americans support the use of US troops to defend Taiwan. And if Israel is attacked by Iran (42%) or its neighbors (41%)—a record low—minorities support the use of US troops to defend Israel. Of course, the lack of support may derive from different causes. Among the American public there is a hesitancy to get drawn into a conflict with a near-peer power like China. And for Israel, its ongoing invasion of Gaza seems to have depressed support. From 2015 to 2021, support was 53 percent for the scenario involving Israel being attacked by its neighbors.1 There is also minority support for sending US troops to Ukraine to help the Ukrainian government defend itself against Russia (29%).    

• 1See Appendix for full trend results.