A win of just a few percentage points in the popular vote could translate into an Electoral College win for Democratic Vice President Kamala Harris, a significant shift from the last two cycles in which Democrats have been losing ground, according to polls and analysis released Saturday night, two days before voting begins on Tuesday, Nov. 5.

The reason, according to experts, is the shifts in voters that may allow Republicans to outperform Democrats when it comes to the popular vote, but that may not translate into more electoral votes for former President Donald Trump and the Republican Party.

“You can win some states that you win by a large margin, but it doesn’t help you anymore,” Jason Roberts, a political science professor at the University of North Carolina, told The Hill, a website that specializes in races and domestic politics. “Winning a state 80-20 doesn’t help any more than winning a state 55-45.”

Democrats have often been the victims of this equation. Since 2000, Democrats have won the popular vote in five of the last six presidential elections, but they have won the Electoral College in only three of those elections.

In 2016, Democratic nominee Hillary Clinton won the popular vote by about 3 million votes but fell short of victory. She outscored Trump when it came to the popular vote in states like California and New York, but that was little consolation when she won by just 232 electoral votes.

To win the "Electoral College" and the presidency, a candidate must secure at least 270 electoral votes (from the Electoral College) out of 535 votes, which is equal to the number of members of the House of Representatives (Congress, 435), and 100 members of the Senate.

24 years ago, (2000 election), then-Vice President (Bill Clinton), Al Gore lost the Electoral College to Republican George W. Bush, even though Gore won the popular vote.

In 2020, President Biden won both, but his advantage in the popular vote and the Electoral College obscured how close the election was. Biden won the popular vote by 7 million and received 306 electoral votes (to Trump’s 229) from the Electoral College, but he only won key states that gave him an advantage of a few tens of thousands of votes at most.

According to Zachary Donini, an expert at the polling firm Decision Desk (DDHQ), the circumstances of the 2020 race allowed Trump to have a chance of winning the Electoral College even if he lost the popular vote by as much as 3.5 points, but Biden won the popular vote by about 4.5 points.

According to experts, this year’s presidential election cycle looks a little different. “If Harris wins the popular vote by 3.5 points, she has an 80 percent or higher chance of winning the presidency,” he told the same site. That’s because polls show her doing better in the so-called “blue wall” states of Pennsylvania, Michigan, and Wisconsin than nationally.

As a result, Harris's margin in the popular vote is unlikely to be as large as those of previous Democratic candidates.

“There’s a lot of random variation here based on this, but the DDHQ model, in our forecast now, pegs this number at between 1.5 and 2.5 percent compared to the 3.7 percent it was in 2020,” Donini said. “So we think it’s going to narrow, but we can’t be absolutely sure.”

Polls indicating demographic shifts in support for each candidate may explain some of the shift.

Harris has not performed as well as Biden with minority voters but has shown some improvement with white voters, Chris Jackson, senior vice president of public affairs at polling firm Ipsos, told The Hill.

This could mean she loses ground in traditional Democratic strongholds, such as California and New York, while still winning them comfortably, but gains ground in the key states needed for her to reach 270 electoral votes.

“Because swing states, especially swing states in the Midwest, have larger numbers of white voters than the country as a whole, this stronger performance with white voters means she has a little bit more room in those states to make up for any potential losses with minority voters,” Jackson said.

He noted that Clinton came within a “throw of a stick” of winning the Electoral College in 2016, losing by a fraction of a percentage point in key states. A two-point popular vote win for Harris, like Clinton, could give her the White House this year. But a one-point win may not be enough.

"I think anything less than two points, that's a real warning sign and very concerning" for Harris, Jackson said.

The possibility remains, though unlikely, that the opposite effect will occur with Trump winning the popular vote and losing the Electoral College.

John Cluverius, associate director of the Center for Public Opinion at the University of Massachusetts Lowell, said he could see either scenario playing out, with Trump narrowly winning the popular vote and Harris narrowly winning the electoral vote if the former president can narrow the traditional Democratic lead in California and New York enough. A margin of just a few percentage points in the popular vote could translate into an Electoral College win for Vice President Harris, a significant turnaround from the last two cycles when Democrats faced a significant disadvantage in the count.

The reason is shifts in voters that may allow Republicans to edge out Democrats when it comes to the popular vote, but that may not translate into more electoral votes for former President Trump and the GOP.

“Because of Republican gains in states like California, New York, and Florida, it may help in the popular vote, and it may even help in the House of Representatives, but it’s not effective from an electoral college standpoint,” Donini, a data scientist at Decision Desk Headquarters (DDHQ), points out.

The “traditional” situation of Harris winning the popular vote but not the electoral vote seems more likely, Cluverius said, but some may underestimate how much some key blue-state areas are talking about issues like immigration, where Republican voters broadly favor Republicans.

“I think people are going in with a lot of assumptions about voters that are based on that historical data,” he said. “Now that’s not a bad thing, but it also means that people are going to assume that what’s going to happen is traditional Democratic strength in the popular vote and traditional Republican strength in the electoral vote.” The amount of split voting can be crucial in determining margins, Cluverius added. Polls have regularly shown Democratic Senate candidates performing relatively strongly relative to the top of the ticket, though split voting in recent history has not happened in large numbers.

"Because there is so much uncertainty in the race, and because the race is so close, we have to have a broad mindset about what could happen," he said.

Jackson noted that more people ultimately support Harris and Trump than will vote for them in the election, meaning the side that can best mobilize its supporters may emerge victorious. Polls can sometimes struggle to measure this adequately, he said, since they can gauge someone’s likelihood of voting but can’t guarantee their behavior.

"We all have to be prepared for a very close race to something that looks like an explosion, which in the context of the poll is still only a few percentage points," he said.