Presidential approval ratings are the most-reported metric in political commentary. Their connection to political outcomes is among the weakest.

At some point today, a cable news chyron will display a number. It will be the president's approval rating, updated to the decimal point, presented as though it were a vital sign on a hospital monitor. A pundit will interpret it. A headline will frame it. A donor will adjust a contribution based on it. And none of them will pause to ask whether the number they are reacting to has any meaningful connection to the political outcome they care about. For most of the uses to which approval ratings are put, it does not.

The Correlation That Sounds Better Than It Is

The standard claim is that presidential approval predicts midterm seat losses. The American Presidency Project at UCSB has tracked the relationship since 1936 and reports a correlation of r=0.61 between presidential approval and House seat changes, with r=0.45 for the Senate. Those numbers sound respectable until you do the arithmetic. A correlation of 0.61 means approval explains about 37 percent of the variance in House seat changes, leaving 63 percent driven by something else entirely. For the Senate, approval explains roughly 20 percent.

A linear model derived from Gallup data makes the weakness concrete. At 40 percent approval, roughly where Trump sits now, the model predicts a loss of about 43 House seats, but with a standard deviation of 22. The 95 percent confidence interval stretches from losing 87 seats to gaining 1. A range that includes both a historic wipeout and a modest gain is not a prediction in any useful sense.

The weakness runs deeper below the 50 percent line. When researchers tested the model separately for approval ratings below 50 percent, it failed its own statistical utility test. The relationship is statistically useful only above 50 percent, driven by a handful of popular presidents whose parties performed well in midterms. Below 50 percent, which is where every modern president spends most of their time and where approval gets cited most urgently, the historical relationship breaks down into noise.

The Counterexamples

If approval ratings were reliable predictors, the exceptions would be rare and explicable, but they are neither. In 2022, Biden sat at roughly 42-44 percent approval. Historical models predicted losses of around 30 House seats and 3 Senate seats. Democrats lost 9 House seats and gained a Senate seat. The model was off by a factor of three in the House and wrong on direction in the Senate.

In 2016, Trump was elected despite holding the highest unfavorability rating of any major party candidate in polling history, at 61 percent unfavorable. His opponent also had historically high unfavorability, which illustrates a deeper problem: favorability is a relative measure being used as an absolute one. George H.W. Bush reached 89-90 percent approval after the Gulf War in 1991 and lost to Clinton eighteen months later.

The Denominator Problem

These failures reflect a structural change in what approval ratings measure, and a numerical illusion in how they are compared to election results.

Trump's approval sits at roughly 35 percent of adults. Commentators compare this to his 2024 vote share of roughly 50 percent and conclude he has lost 15 points of support. But these numbers have different denominators. Approval polls sample all adults. Vote share is a percentage of the roughly 62 percent of adults who actually voted. Trump received about 50 percent of that 62 percent, meaning approximately 31 percent of all adults cast a ballot for him. His 35 percent approval rating is, by the measure that matches the poll's sample frame, higher than his actual adult-population vote share.

The entire "he's lost his base" framework rests on this comparison. When a commenter points to 35 percent approval and says Trump has shed the new voters who put him over the top in 2024, they are performing a subtraction across incompatible units. But this isn't about Trump, there is a deeper change afoot.

Why Approval Has Become a Constant

The deeper structural issue is that approval has become inelastic. In the 1950s through the 1980s, it moved with events and economic conditions. Eisenhower, Kennedy, Johnson, Nixon, Carter, and Reagan all saw approval ranges of 30 to 40 or more points across their terms. The electorate was less sorted, more voters were persuadable on the merits, and approval captured something resembling an evaluation of performance.

That elasticity is gone. Trump's first term was the most stable approval rating in Gallup's tracking history; he barely moved from the low-to-mid 40s across four years regardless of events. Obama ranged only about 10 points across eight years. Roughly 40 percent of adults will approve and roughly 50 percent will disapprove of any president, regardless of performance, because approval has become a proxy for party identification. The remaining 10 percent in the middle is responsive to conditions, but their movement is swamped by the partisan anchors on both sides.

The Legislative Connection Is Even Weaker

If approval had limited value for predicting elections, it might still matter for governing. The academic research does not support this. The most rigorous study of the question found that approval affects legislative outcomes only on high-salience, low-complexity issues, essentially easy votes where members of Congress worry about being on the wrong side of a popular president. On complex legislation or anything where the member's constituency has a distinct interest, presidential approval has no independent effect.

The current Iran situation provides a clean test. The War Powers resolution vote went 53-47 along party lines in the Senate with Trump at roughly 35 percent approval. If approval drove legislative behavior, you would expect some Republicans in competitive states to break with Trump on a politically toxic war vote. Only Rand Paul defected, because his calculation had nothing to do with a national polling number and everything to do with his own primary electorate and donor base.

What Approval Ratings Actually Are

Strip away the forecasting pretensions and ask what approval ratings functionally do. They give cable news a number to put on screen, pundits a hook for commentary, donors a signal to calibrate contributions, and the polling industry a recurring revenue stream from media clients who will always pay for a new number regardless of whether it means anything. What they do not reliably do is predict elections, forecast legislative outcomes, or measure the thing they claim to measure.

The next time a headline announces that the president's approval has hit a "new low," consider what that information enables you to do. Can you predict the midterms from it? Not from approval alone, and not at these levels. Can you predict legislative outcomes? Not except on easy votes. Can you even be confident the number will hold? Bush's 40-point drop from 1991 to 1992 says no.

What you can do is nod along with commentary that tells you what you already knew: that the president's opponents disapprove and his supporters approve, in proportions that have barely moved since inauguration day. That is what the number describes. Everything else built on top of it is narrative dressed in decimal points.