(NewsNation) — Presidential historian Allan Lichtman, who had predicted that Vice President Kamala Harris would win the 2024 presidential election against former President Donald Trump, says he is “taking some time off to assess why” he was wrong this time.

In a statement to NewsNation, the American University professor said, “I am taking time off to assess why I was wrong and what the future holds for our country.”

Lichtman had correctly predicted nearly every presidential race since 1984 using a formula of 13 true-or-false questions.

During a live stream on election night, as the results were revealing a Trump victory, Lichtman repeatedly said, “I don’t get it.”

“Oh, the democracy’s gone,” Lichtman said as Trump was on his way to win major swing states. “Once democracy’s gone, it’s almost impossible to recover. The way to recover is by the dictators losing wars.”

In a Wednesday post on X, the professor told his viewers to “tune in on Thursday at 9 PM Eastern for a discussion of what happened and what the future holds for America.”

Why Allan Lichtman predicted a Kamala Harris win

The historian who devised the “Keys to the White House” formula has correctly predicted nine of the last 10 presidential elections, including Trump’s victory over Hillary Clinton in 2016.

Lichtman confirmed several keys favoring Harris, including the short-term economy key (no recession in election year) and long-term economy key (per capita growth exceeding previous terms’ average).

While Democrats lost the party mandate key due to their 2022 House losses, Lichtman previously told NewsNation they salvaged the crucial party contest key by uniting behind Harris.

“Maybe the Democrats listened to me … they united overwhelmingly behind Harris, avoiding the loss of the contest key,” he said.

How does ‘Keys to the White House’ formula work

Developed in 1981 with mathematician Vladimir Keilis-Borok, Lichtman’s formula of 13 keys to the White House has helped him make overwhelmingly accurate predictions ever since.

He says that if the party holding the White House loses six of those keys, that party will probably lose the election.

Allan Lichtman’s keys to the White House:

Party mandate

Party contest

Incumbency

Third party

Short-term economy

Long-term economy

Policy change

Social unrest

Scandal

Foreign/military policy failure

Foreign/military policy success

Incumbent charisma

Challenger charisma

Allan Lichtman takes shot at Nate Silver

Lichtman took a swipe at fellow prognosticator Nate Silver on Wednesday, saying, “Unlike Nate Silver, who will try to squirm out of why he didn’t see the election coming, I admit that I was wrong.”

Silver’s analysis had the race as a statistical toss-up, though he hedged that “close polls don’t necessarily predict a close result.”

Silver had previously written his gut sense was that Trump would win.

NewsNation’s Katie Smith and partner The Hill contributed to this report.