The US midterm elections on November 3 could leave Donald Trump with less room to legislate and financial markets with little relief. An advance by the Democrats would constrain his domestic agenda, but the weeks after the vote could bring fiscal confrontation and renewed military action against Iran.

For investors, the response to the result may matter more than the result itself.

Markets enter the election after a technology-led sell-off, with a hawkish Federal Reserve and oil above $100 a barrel. That starting point makes the historical tendency for equities to rally after midterms a less reassuring guide to what follows.

National polling suggests sentiment has swung by around 10–11 percentage points towards the Democrats. They need to gain only three seats to win the House of Representatives, while Republicans hold nearly 30 districts that Trump won by less than 11 percentage points. Prediction markets imply a net gain of 21 seats for the Democrats, taking their total to 236, a majority comparable to 2018 and more comfortable than those held since 2021.

The Senate remains harder to call. New York Times/Siena polls put Democrats ahead in most of the seven battleground races, and DecisionDeskHQ assigns a 60% probability to a takeover by the Democrats. Yet decisive contests remain within polling margins of error, and past errors in Republican-leaning states warrant caution. Most of the 35 seats being contested are in deeply Republican states, making the apparent shift striking.

Neither outcome is assured.

Redistricting has raised the hurdle for Democrats in the House, with a May analysis suggesting they might need a national vote lead of about four percentage points to be competitive. Polling errors and late-deciding voters could still alter control of either chamber.

A House controlled by the Democrats would nevertheless impose meaningful constraints on Trump’s agenda through its legislative, spending and investigative powers. Control of the Senate would add the ability to block judicial and cabinet appointments. Its incremental effect on legislation would be smaller, since Senate passage generally requires bipartisan support and Trump would retain his veto.

Fiscal Friction
Those constraints could produce compromise as well as confrontation. Spending authority must be extended and the debt limit raised, giving Democrats opportunities to press for changes on Iran, tariffs, spending cuts and health benefits. Reversing cuts in last year’s fiscal package could add spending equivalent to an estimated 0.25% of GDP in 2027. Discretionary spending agreements or expanded health insurance subsidies could add modestly to that.

The immediate funding deadline arrives before a new Congress takes over. The stopgap runs only until December 11, while the lame-duck session begins on November 9 with Republicans still in control.

The aftermath of the 2018 election offers a warning: after Democrats won the House, a partial shutdown lasted from December 22, 2018, to January 25, 2019. Funding and debt-limit confrontations could become significant sources of volatility.

Tariff policy would also remain difficult to reverse.

Slim bipartisan majorities in both chambers have already supported curtailing some tariffs, and Democrats are likely to force further votes. Overriding a presidential veto requires two-thirds support in each chamber, however, leaving trade policy largely in executive hands.

For US Treasuries, a divided government could reduce the likelihood of new deficit-financed spending and support longer-dated bonds, even if specific compromises modestly increase expenditure. A shutdown or prolonged budget fight could weaken that support. The initial dollar response may be muted because markets already anticipate the Democrats taking control of the House, leaving inflation, growth and the Federal Reserve as the main drivers.

Equity investors have a strong historical record to draw on. Since 1974, the S&P 500 has gained an average 5.7% in the three months after midterms, rising in 11 of 13 cases. Over six months, the average gain has been 12.4%, with increases in all 13 cases.

Valuations and monetary policy make that record less comforting this time. The Shiller cyclically adjusted price-to-earnings ratio is near its second-highest level on record. In 2022, the last midterm year accompanied by Federal Reserve rate increases, the S&P 500 lost about 19% over the year. Against the current backdrop, legislative gridlock could leave US equities vulnerable to a further correction of 5–10% from last week’s closing levels.

Iran Exposure
The more consequential risk may emerge from Trump’s response to an electoral setback. Iran’s bargaining position may weaken once voting is over, and a defeat could prompt Trump to pursue another round of military action against Iran’s nuclear facilities. Netanyahu, strengthened by his recent performance in Israel’s elections, could join such an operation. The possibility of renewed escalation after November 3 remains a significant market risk.

The election result itself may do little to move the dollar index or US Treasury yields. Renewed conflict could nevertheless lift both the dollar and crude prices, weakening currencies and sustaining capital outflows in energy-importing emerging markets. For these economies, any relief from greater legislative restraint in Washington could be overwhelmed by another external shock.

That risk leaves India’s current bond relief rally vulnerable, strengthening the case for exiting long positions. The rupee may struggle to sustain levels stronger than 94.5 against the dollar and could move towards 97 if Brent crude rises above $120 a barrel.

The Reserve Bank of India’s forward book adds another constraint.

The latest Special Data Dissemination Standard data show its net short forward position rose by $39.2 billion to $239.2 billion at end-September. That large position suggests limited room for the RBI to bring down dislocated and elevated forward premia. One-year dollar/rupee forward premia are likely to remain in a 4–4.5% range in the near term, with renewed war potentially pushing them towards 5%.

A change in control of Congress would restrain legislation more readily than it would resolve a confrontation with Iran. For Indian markets, the danger is that a widely anticipated political outcome is followed by an oil and dollar shock, leaving the relief in bonds and the rupee short-lived.