Republicans are getting a boost for their hopes of winning the White House and down-ballot. With 21 days until Election Day, the number of Americans who self-identify as Republicans tops those who identify as Democrats for the first time in four decades.

Ahead of the 2016 election, Democrats held a three-point advantage, according to CNN’s data analyst, Harry Enten. In 2020, Democrats had a six-point advantage. However, he cites Gallup data which shows that Republicans currently have a one-point advantage over the Democrats. 

Mr. Enten also said the average gap in party identification when Democrats win is eight points, and when Republicans win, they usually have a three-point deficit in party identification.

Trump’s campaign shared a video clip of Mr. Enten breaking down the numbers and, citing unfounded claims about widespread election fraud in the last election, wrote it was evidence of a coming victory that would be “too big to rig.”

The last time the party affiliation trends favored Republicans was in 1984 when President Reagan won re-election in a landslide, winning 525 electoral votes to Walter Mondale’s 13. 

Data from Pew Research shows the number of Americans who identified as registered with either party was tied in 2004 when President Bush won his re-election bid. 

While political observers look at many metrics to try to glean information about who will prevail in an election, such as voters’ satisfaction with the economy or the incumbent president’s approval rating, Pew says there is a “strong” relation between party affiliation numbers and who wins the election. 

The party identification data at the national level comes as Republicans have been touting wins at the state level outpacing Democrats for new voter registrations. In Florida, for example, 1 million more voters are registered as Republicans than Democrats, a significant shift from 2020, when Democrats had roughly 97,000 more registered voters.

Despite Republicans’ national advantage in party affiliation, polls still show a close race between Trump and Vice President Harris. An NBC News poll released Sunday found the two candidates tied at 48 percent with a margin of error of 3.1 percentage points.

A poll from NBC in September found that Ms. Harris was leading the former president by five percentage points. 

However, a CBS News/YouGov poll found that Ms. Harris holds a three-point lead nationally and a one-point lead in the battleground states, with a margin of error of 2.3 percentage points. 

In RealClearPolitics’ average of polls in North Carolina, Arizona, Nevada, Georgia, Pennsylvania, Arizona, and Michigan, neither candidate has more than a one-point lead.