There are more than three months until Election Day. The Democrats could conceivably recoup and win the election, but the possibility of a “red wave” sweeping Republicans to victory in both the House and Senate can’t be dismissed. In this fluid season, anything could happen.

The stock market, however, is remarkably indifferent to the nation’s political fortunes. On Monday there were big moves in stocks perceived as benefiting from a Trump presidency, but that exuberance didn’t last. Instead, the market seems to be focused on issues that have little to do with politics, like the possibility of a Federal Reserve rate cut, heartening corporate earnings reports or the allure of artificial intelligence stocks.

The Trump Market

On May 16, former President Trump’s odds of victory began to surpass those of President Biden’s on the PredictIt market, and the gap has widened since the debate, raising the possibility of a Republican landslide. From May 16 through Tuesday, the S&P 500 gained almost 7 percent.

Mr. Trump has an established record, and the markets evidently find it comforting.

That may seem strange. After all, Mr. Trump is the first former president to have been convicted of a felony, and he has a well-documented propensity to stretch the truth, if not deny it entirely. If re-elected, he promises to disrupt the status quo on immigration, tariffs, trade, taxes, regulation, U.S. support for Ukraine and NATO and countless other matters. A Trump victory could require wholesale readjustments in thinking about the economy — and the markets are said to abhor uncertainty.

But apparently of greater import for traders is the reality that Mr. Trump presided over a raging bull market in stocks, albeit one interrupted by the onset of the coronavirus pandemic.

That Trump market rally really began months before his inauguration in January 2017. At first, as returns trickled in on Election Day in November 2016, the stock futures market cratered when it became apparent that former Secretary of State Hillary Clinton, the presumed winner, was actually losing to Mr. Trump.

But then, shortly after 2 a.m., the new president-elect uttered emollient words, pledging to work together with Mrs. Clinton and other Democrats “to unify our great country.” Obviously, that harmonious political future never happened — but the market immediately started to levitate.

In fact, the stock market during the Trump administration ranks fourth among all presidents since 1901, using Dow Jones industrial average returns calculated by Bespoke Investment Group, a financial market research company. Stocks gained 12 percent, annualized, under President Trump. That placed him behind only Presidents Calvin Coolidge, Bill Clinton and Barack Obama.

By comparison, so far in the Biden administration, the annualized gain is 7.1 percent, according to FactSet, a far more pedestrian figure. If that stock market growth rate were to continue until Inauguration Day, the return for Mr. Biden’s first (or only) term would be absolutely middling — ranking 11th among 21 presidents since Theodore Roosevelt became president after the assassination of William McKinley.

Sound and Fury

But I think it’s more likely that the market doesn’t care much one way or another.

As I’ve noted before, the stock market is amoral and apolitical. There have been market misfortunes under both political parties but, for the most part, the stock market has done well under both Democrats and Republicans.

It’s easier to find patterns in the market than it is to prove that they matter.

A comparison of market returns during the Obama and Trump administrations is startling. “The performance of sectors during the presidencies of Obama and Trump shows that the impact of the person in the Oval Office may not be as significant as often assumed,” Bespoke Investment Group said. “While the two were polar opposites in terms of policy and style, the stock market sectors that led and lagged during each president’s tenure were largely the same.

“In President Obama’s eight years, the three top performing sectors were consumer discretionary, technology and health care; for Trump, the three top performing sectors were the same,” the group said. “Likewise, energy was the worst performing sector for both presidents, and financials was in the bottom three.”

Similarly, former President Trump and President Biden aren’t remotely alike in terms of policy, character, style or adherence to the rule of law. Countless Wall Street reports say, quite logically, that specific market sectors may do better under one leader than the other, though the more I look at it, the less I’m sure even of that.

President Biden has taken strong positions on climate change. Former President Trump has downplayed the problem when he’s acknowledged it’s a problem at all, and he has favored fossil-fuel companies. Yet consider the returns of exchange-traded funds that track the clean energy and fossil-fuel stock sectors:

• The iShares Global Clean Energy E.T.F.: 26.6 percent, annualized, under Mr. Trump; minus 19.8 percent, annualized, under Mr. Biden.
• The SPDR S&P Oil & Gas Exploration and Production E.T.F.: minus 13.3 percent under Mr. Trump; 26.9 percent under Mr. Biden.

The Ukraine war and a burst of global inflation had more to do with the rising price of oil and the surge in fossil-fuel stocks than any Biden administration policies, in my estimation. And the increasing popularity and profitability of clean energy companies during the Trump administration didn’t stem from administration policy, which favored fossil-fuel companies.

I think the only reasonable conclusion, and one that savvy investors make all the time, is that market returns and presidential ambitions don’t necessarily go hand in hand.

Gridlock, or a Sweep

It’s frequently said that the markets prefer gridlock, meaning a divided government, with the opposition party controlling at least one house of Congress and preventing presidents from achieving all they desire. With limited interference from Washington, companies can do what they do best: make profits. Or so the thinking goes.

History doesn’t entirely bear this out, though. Adjusting for inflation, from 1901 through January, the Dow gained 7.1 percent, annualized, when Republicans had unified control; when Democrats had it, the Dow rose 2.8 percent, annualized, according to Ned Davis Research, another financial research firm. Unified government was fine with the stock market, especially under Republicans.

This helps explain why the market has been so calm lately. It may be concentrating on economic issues: declining inflation, the increasing likelihood of Fed rate cuts, corporate profit growth and the tantalizing prospect of A.I.-driven productivity gains.

This will turn out to be shortsighted if the election has economic consequences so severe that profit-seeking markets can’t cope with them. I expect a happier future — yet think it important to stash enough cash and high-quality bonds to ride out several years of potential trouble. For the long-term, though, investing in the entire stock and bond markets through low-cost index funds is probably the way to go.