The biggest lesson of this month’s sweeping Democratic election victories is that President Donald Trump is continuing to cast an outsize shadow over every other election during his presidential term.

Over the past several decades, the general trend has been that attitudes toward presidents from both parties have exerted growing influence over other elections. But even against that broader trend, Trump stands out.

In this month’s elections, as in 2018 and 2020, voters who disapproved of Trump’s job performance voted for the other party’s candidates at an even higher rate than for any other recent president. The power and persistence of that pattern — in both the midterm and presidential year elections during Trump’s first term — suggests that the single most important variable in most midterm contests next year will be whether more voters in that race approve or disapprove of his record in the White House.

“I think he’s at the center of the stage and the spotlight,” said Sean Clegg, a senior adviser to California Gov. Gavin Newsom. “Trump is the story.”

Even many Republicans agree. “Donald Trump has so thoroughly dominated American politics for the last decade, and he has been so demanding of complete loyalty from anyone running as a Republican, that views of the Republican Party and Republican candidates are synonymous with views about Donald Trump,” said veteran GOP pollster Whit Ayres.

That has benefited Republicans in red states where he’s helped the GOP consolidate almost unprecedented control. But the results in Virginia and New Jersey offered a pointed reminder that Trump’s indelible stamp on the GOP may once again become a burden next year on more politically contested terrain.

President Donald Trump speaks with reporters before boarding Air Force One at Lehigh Valley International Airport, on August 3, in Allentown, Pennsylvania. Julia Demaree Nikhinson/AP

A deepening connection

The correlation between attitudes toward the president and the outcomes of other elections has grown much more powerful over roughly the past half century. Through the 1980s and 1990s, it was fairly common for voters to separate their views of the president from how they voted in House, Senate and gubernatorial elections.

Exit poll results from that era quantified those divided loyalties. In the 1978 midterm election, for instance, Republicans in races for the House of Representatives won only 60% of voters who disapproved of Jimmy Carter’s performance as president — meaning 37% of voters unhappy with Carter still voted for other Democrats.

Over the next