The S&P 500 index has recorded a 1% increase year to date, positioning itself within a narrow margin of its all-time peak. Despite this apparent strength, several economic and political factors may undermine market stability as 2026 unfolds. Among these are the consequences of tariffs implemented under President Trump's administration, prevailing high index valuations, and the uncertainty introduced by midterm elections.
President Trump has publicly endorsed the tariffs as beneficial to the U.S. economy, asserting that they have fostered remarkably robust economic growth. Specifically, in an editorial published in The Wall Street Journal early in 2026, he characterized the average tax on U.S. imports as having quintupled under his policies and suggested exporters bear the cost. However, a closer inspection of economic indicators calls these assertions into question.
The economy experienced a contraction in the first quarter of 2025, although growth rebounded in the second and third quarters. When combined, the total real gross domestic product (GDP) growth over the first nine months of 2025 reached 2.51%. This figure, while positive, falls below averages observed over longer horizons: the preceding ten years averaged 2.75% growth, the previous thirty years 2.58%, and the past fifty years 2.84%.
Notably, expenditures related to artificial intelligence during this period contributed approximately 0.97 percentage points to GDP growth, as reported by the Federal Reserve Bank of St. Louis. Removing this factor suggests that the underlying economy expanded by merely 1.54%, highlighting a comparatively tepid growth rate absent AI-driven investment.
In his editorial, President Trump claimed that the tariff costs were predominantly borne by foreign producers and middlemen, citing a Harvard Business School study that purportedly shows that at least 80% of tariff expenses fell on non-U.S. entities. However, a direct reading of the cited study contradicts this claim.
The referenced Harvard report explicitly states that American consumers absorbed up to 43% of the tariff burden, with the remainder being absorbed by U.S. firms. There is no indication within the report that foreign exporters shouldered a significant share of these costs. This discrepancy suggests the president’s statement misrepresents the study's findings.
Summarizing these observations, the claim that tariffs have strengthened domestic economic growth is not strongly supported by the available data. The GDP growth rate in the first three quarters of 2025 was below historical averages, and AI-related spending accounts for a substantial portion of the growth achieved. According to assessments from Goldman Sachs, excluding AI investment, the U.S. economy would have experienced minimal growth during this timeframe.
Turning attention to the stock market valuation, the S&P 500 currently trades at a forward price-to-earnings (P/E) ratio of 22.2, which is considered high by historical standards. Over the last four decades, such elevated forward P/E ratios have only been sustained during the dot-com bubble and the COVID-19 pandemic—both episodes that culminated in bear markets.
Market expectations anticipate earnings growth acceleration for S&P 500 companies in 2026, thereby justifying the current high valuation to some degree. Nevertheless, this suggests that the market’s pricing already assumes strong corporate financial performance. Should the tariff-driven economic pressures result in earnings falling short of these expectations, the S&P 500 could experience sharp declines.
In addition to economic indicators, election cycles have historically influenced market volatility. Midterm election years typically coincide with uncertainty regarding fiscal, trade, and regulatory policy directions. Historical data reveals the S&P 500 has undergone a median intra-year drawdown of approximately 19% during such years.
This pattern implies a roughly 50% probability that the market could decline by nearly one-fifth during 2026. The tendency for the incumbent party to lose seats in Congress during midterms accentuates this uncertainty and potential market stress.
In conclusion, several headwinds confront the U.S. stock market as 2026 progresses: persistently high valuations, the economic effects of tariffs, and the unpredictability of midterm election outcomes. Combined, these factors elevate the risk of a significant market contraction or crash.
However, history provides a perspective of cautious optimism; previous draws in stock valuations during similar conditions have presented rewarding entry points for investors. While uncertainty prevails, past precedent suggests that market downturns may also offer opportunities to build positions with long-term benefits.