Divided We Stand? Implications of the 2026 Midterm Elections for Transatlantic Security

With the midterm election results nearly settled, Democrats are poised to take control of both chambers of the US Congress in January 2027. This landslide victory for the Democratic Party is widely seen as a strong rebuke of the administration’s foreign policy agenda, and will mark the first time that US President Donald Trump has had to govern with both the House of Representatives and the Senate controlled by the opposition party.

Historically, US elections are rarely defined by foreign policy. American voters, to the degree that they diverge from their preferred political party, tend to vote on economic issues and overall feelings about whether the country is on the right track (factors known as “the fundamentals”). And indeed, the 2026 midterm results may be the exception that proves the rule. Voters’ top concerns reflected the high cost of living and gas prices, but those economic issues could be and were directly traced to the administration’s foreign policy agenda: namely, the war against Iran and Trump’s tariff policies.

What does this mean for the future of US foreign policy and the transatlantic relationship? Here are three things that Europeans need to know.
 

1. The president still has a lot of power over foreign policy 

As GMF Visiting Senior Fellow J.C. Lintzenich pointed out last week, the US constitution affords significant latitude to presidents in the conduct of foreign policy. Presidents hold the preponderance of power in foreign affairs, and have historically leaned into their head-of-state role during their final two years in office as they work to cement their legacy. When they face opposition in Congress, this trend is even more pronounced as it remains the final arena in which they can exercise significant unilateral influence.

Europeans should therefore expect Trump to stay engaged in international affairs, up to and including using force to achieve quick victories à la the Maduro raid in Venezuela. Indeed, the administration has already hinted that it will restart the war in Iran in the wake of the midterm elections—a move that is reminiscent of US President George W. Bush’s Iraq “surge” strategy following a resounding midterm defeat in 2006. Yet Europeans should not think that this will lead to across-the-board interventionism or a more credible deterrent. In the event of a Russian escalation in Ukraine, it would still be the president's responsibility to determine how to interpret the United States’ Article 5 NATO commitments, for example, and Trump’s history of commitment to the treaty has been uneven at best. Overall, Europeans should not expect any significant change in the administration’s rhetoric or actions toward European allies. While an opposition Congress may be able to limit some of the more radical proposals being floated by the administration, it simply does not have the toolbox necessary to stop US retrenchment from Europe.
 

2. Congress can still serve as a critical check on executive power

Although Congress has only a limited number of tools at its disposal to exercise influence over foreign policy, this Congress is coming in with a mandate to exercise those options in a vigorous way. Polling that the Democracy and Security Network conducted earlier this month revealed that supermajorities of Americans—including a majority of Republicans—saw Congress as the American institution most responsible for ensuring that the president is held accountable for issuing unlawful orders. Democrats in the majority will therefore almost certainly use congressional oversight mechanisms to launch investigations into key foreign policy issues, particularly the Iran war. Democrats may start by examining Pete Hegseth's role in the conflict, focusing on controversies around undisclosed casualties, munitions shortages, and the lack of planning for an exit strategy. The new Congress will also almost certainly hold multiple votes attempting to hold Trump accountable for the Iran war through the War Powers Resolution. Finally, Democrats will no doubt try to place significant limits on presidential control over the military—including control over adjustments to troop levels—as part of the must-pass National Defense Authorization Act (NDAA).

A Democratic-controlled Congress is also likely to exercise significant control over the “power of the purse” by leveraging its role as federal appropriator. Unlike in 2006, when Democratic majorities in Congress agreed to fund Bush’s surge in Iraq, Congressional Democrats are much less likely to agree to fund any resumption of the conflict against Iran. As a result, Republicans will likely work out a deal on the Iran supplemental funds request in the lame duck period, with the understanding that any future appropriations for the war will almost certainly be either “dead on arrival” or subject to extreme oversight provisions.

With regard to Ukraine, the new Congress may also force the president to take action through spending, legislation, and oversight. The “Graham Act”, which places wide-ranging sanctions on Russia over the Ukraine War, was passed in September 2026 but the administration has delayed its implementation. Given that support for Ukraine receives such strong bipartisan support in Congress, this is an area where veto-proof majorities may be most likely to occur. The next Congress could therefore use its appropriations, oversight, and authorization powers to force the administration to faithfully implement sanctions and earmark military aid for Ukraine, with penalties built into next year’s NDAA should the administration refuse. They may also conduct investigations into the Russian “diesel deal” and how Starlink access for Ukraine was deactivated, and they could compel Elon Musk to appear before an investigative committee.

Finally, Congress can play a significant role in the appointment of personnel in key foreign policy positions, and will likely start with Secretary of Defense Pete Hegseth. There is precedent for this kind of shake-up going back again to 2006: The day after Republicans were handed massive midterm losses over the unpopularity of the Iraq War, then-Secretary of Defense Donald Rumsfeld resigned his position. And while there is little evidence to suggest that Hegseth intends to follow Rumsfeld’s lead, there has been widespread speculation that Congressional Democrats are ready to keep major spending and appropriations agreements from passage until Hegseth is forced out of office.
 

3. Gridlock will make transformative change almost impossible

All politics are local in the United States, and Democrats will probably spend the majority of their attention and political capital on domestic issues rather than foreign policy. Efforts to address affordability issues will almost certainly result in conflict between Congress and the president over budgets as Democrats seek to provide relief by expanding the social safety net. Moreover, Democrats are likely to insist on significantly more accountability from the executive branch on the funding it does provide, and this may result in impasse. The likely result of divided government in Washington, therefore, will be increased difficulties in passing budgets. Europeans (and Americans) should expect more government shutdowns, followed by the passage of continuing resolutions (CRs), followed by more budget standoffs. Congressional Democrats are also likely to focus on investigations beyond the foreign policy realm, particularly on issues related to corruption—which ranked high as a priority for voters in the midterms. This could therefore occupy a significant amount of the president’s energy and attention.

This kind of gridlock could have significant implications for Europe as the continent undertakes its biggest defense strategy review since the end of the Cold War. As many in the US defense space have articulated, a reliance on CRs and late budgets will have major implications for the United States’ ability to fund major initiatives and shift priorities. For some Europeans, this may be welcome news as US defense funding levels in Europe could remain steady. For others, however, the unpredictability of the US budget-making process could prove destabilizing as new European defense initiatives seek to develop strategic complementarity with the United States. This could be especially impactful in areas that require collaboration, synchronization, and major upfront and prolonged investments, such as artificial intelligence initiatives and new weapons systems and platforms.

Looking Forward: The Fight for 2028

It is well established by now that the traditional US foreign policy consensus that privileged engagement in European affairs is, at best, waning. While Americans still believe in the value of alliances, there is little appetite in the base of either party for more interventionist policies. Indeed, the resounding rebuke of the administration's policies in Iran in this week’s midterms—even and perhaps especially in areas of the country considered to be Trump’s MAGA base—suggest that the United States still has major questions to ask and answer about its role in the world. The next two years, therefore, will see significant debates within both the Republican and Democratic parties about America as a global actor, and party leaders will develop new narratives about the direction and purpose of US foreign policy. For Europe, the transatlantic relationship may hang in the balance.