As the dust settles on the 2026 US midterm elections, two facts are clear: First, the Democrats have achieved a historic victory – and second, Donald Trump remains president for the coming two years.

That means Congressional Democrats will have three legislative lanes to pursue: The first is constraining Trump. This includes doing what they can through Congress to bring the Iran war to a conclusion, blocking many of his nominations, particularly to the judiciary, ending ICE’s aggressive immigrant detentions, and pursuing oversight of Trump and his allies’ financial networks and alleged corruption.

The second lane will be about demonstrating a positive policy agenda to inform the 2028 cycle, when Trump will be off the ballot. This is more about “messaging bills” focused on social issues, but could also include economic measures such as tax reform proposals, as well as significant reforms of US global defence cooperation authorities and shifts to major foreign policy questions, such as aid to Israel.

The final lane will be that – perhaps narrow – set of issues where bipartisanship and cooperation with the White House is possible. Putting guardrails around America’s burgeoning artificial intelligence (AI) sector may fit in that box, although some of Trump’s biggest funders are likely to do what they can to derail progress.

Many of the bills that will be put forward in the first and second lanes would be subject to presidential veto. Others will be toned down, as the Democratic establishment seeks to resist the progressive left’s ambitious agenda. These dynamics are likely to make the upcoming Congress less productive.

On foreign policy, in particular, Congress is able to pass just a slim set of acts without presidential endorsement, such as war powers legislation, limiting the president’s ability to wage war without Congressional approval; or measures like the recent Senate resolution advanced by Maryland Democrat Chris Van Hollen to demand reporting on Israel’s human rights record; or committee subpoenas, which can be used to investigate members of the Trump administration for wrongdoing. But they are likely to be ignored or stonewalled by the White House, leading to months, if not years, of fruitless litigation.

That is not to say that introducing “stand-alone” bills on issues, such as arms transfers to Israel, would not be important even if blocked by the president. They remain useful both for framing the conversation and for getting members of Congress on the record and establishing consensus positions.

In the Senate, where several incumbents are likely to throw their hats into the upcoming presidential nomination contest, such bills could be used to highlight the progressive credentials of some candidates – or to force more conservative members into awkward positions. That might ultimately make a difference in terms of the framing and debate for the 2028 election – and a potential Democratic administration thereafter. But it will not change anything in the immediate term.

There are at least three tools available to legislators where a fierce – and perhaps impactful – debate is likely to play out. The first is that enabled by Congress’ constitutional “power of the purse”.  If the current Republican majorities do not manage to pass an annual funding bill by the end of this calendar year, the Democrats will have both the current year and the next two years of US government funding under their control.

This includes, of course, Israel’s annual allocation of $3.3bn, which Trump himself put into doubt in a surprising and as yet unclarified statement on election day. If nothing else, the president’s call for an end to security assistance to Israel may accelerate what would likely have been a steady reduction under Democratic leadership.

The new Congress will also be able to reconsider a range of funding restrictions and requirements, such as the prohibition on funding the United Nations agency for Palestinian refugees (UNRWA), or the limitations on funding the Palestinian Authority.

Passing such bills will not be simply a matter of partisan rancour — we can expect some pretty tough battles to play out within the Democratic caucus itself on some of these issues. Then it is another matter of whether the Trump administration adheres to the law with the funding it ultimately receives.

The second area to watch is that of oversight. With the majority in hand, Democrats in the House and Senate can set the agenda – deciding which actions by the Trump administration are ripe for investigation, identifying witnesses, and using the committee gavels to drive the public debate.

Party leadership will be eager to focus on the issues that are most damaging to the current administration and its likely candidates for succession, such as Vice President JD Vance or Secretary of State Marco Rubio, while being least disruptive to party unity.

And because the system relies on seniority, control of the agenda of Congressional committees that can investigate the government would rest with Democratic establishment members who would be less likely than their newer or younger peers to be critical of the US-Israel relationship.

That said, it is hard to imagine a Democratic Congress that does not at least conduct oversight of Trump’s Board of Peace and its opaque sources of funding and influence. Another likely topic is the question of US involvement in the current war with Iran.

What the Democrats choose not to pursue via oversight will also be important: The weaponisation of anti-Semitism by the current and previous Congress to attack the US education sector and civil society should come to an end under the next Congress. Though certainly Democratic leadership will be keen to find ways to demonstrate that they still care about genuine concerns from the Jewish community, one would hope that these are pursued with a more concrete grounding in reality and shared security than as a tool for repressing pro-Palestinian speech.

But many in the Democratic base would like to see the party do much more – including holding hearings into the US role in enabling Israel’s genocide in Gaza, a topic that would ensnare senior officials from the Biden administration in a very public accounting that the establishment is keen to avoid.

Here is where the details of the outcome of the midterms will truly matter. While there is no doubt that the centre point of the Democratic Congressional caucus has shifted to the left for the upcoming 120th Congress, particularly in the House, the size of the majority matters.

As recent Republican Houses have demonstrated, a small majority is a challenge for the speaker, as it empowers a small group of members to exert significant leverage through the threat of withdrawal of their support for basic procedural steps that are typically decided on a partisan vote basis.

As a result of the midterms “blue tsunami”, however, the Democratic majority is secure enough that leadership will have to make few real concessions to the left of their party, likely teeing up some tense, and almost inevitably public, tussling in the coming two years, particularly when it comes to appropriations bills.

In short, the Democrats’ campaign for legislative power has been a success, but particularly in the face of an imperious White House that has shown little interest in even longstanding legal precedent in its deference to Congress, it remains incomplete.

At the same time, being the party locked out of power has enabled the Democrats up to this point to dodge some degree of the internal wrangling that is already long overdue on key issues, such as foreign policy on Israel.

A majority in Congress may not give them complete control – but it does mean they will now own the legislative branch’s decisions. Whether they demonstrate a meaningful and proactive shift – or let themselves be constrained by establishment conservatism – may define the viability of their path to further electoral success in 2028.

Either way, the American people will be watching what Democrats do and do not do – as will the Republicans who, as Trump enters his “lame duck” years, are likely to undergo an evolution of their own on these key issues.

This makes progress in the coming Congress all the more acute an issue for the Democrats. The challenge for them is simple: take credible leadership on driving change or face the very real possibility of being outflanked by the “America First” right.

The views expressed in this article are the author’s own and do not necessarily reflect Al Jazeera’s editorial stance.