Analysis by Chris Cillizza, CNN Editor-at-large

(CNN) -- Eight days from the 2020 election, the story is just how many people are already voting.

Videos and photos of massive lines of people waiting to vote have gone viral. Sharing your "I voted" sticker is all the rage on social media. And the numbers are bonkers: According to data from CNN, Edison Research and Catalist, more than 60 million pre-election votes have been cast, and 33 states already surpassed their pre-election vote totals from 2016. (In 2016, 58 million total votes were cast early -- either in person or by mail.)

Numbers like those raise one obvious question: Just how high will turnout be in 2020? And one other follow-up question: Could 2020 break voter participation records?

The short answer to those two question is "very high" and "yes, potentially." The longer answer is, well, longer.

First off, historical comparisons on turnout are a) difficult and b) dicey. Difficult because the data collection systems in the 19th century weren't all that great. (Slow internet speeds back then!) And dicey because when we are talking "eligible voters," that excludes African Americans until 1870 and women until 1920.

Because of these issues, most political scientists and historians tend to go back only as far as the start of the 20th century when creating historical comparisons for our modern era. (Again, that includes two decades of women not being allowed to vote. But I digress.)

The modern standard for presidential turnout is 1908, when 65.7% of eligible voters cast a ballot in the race between William Howard Taft and William Jennings Bryan. (The seat was open when Teddy Roosevelt announced, just before his 1904 victory, that he would not run again.) The actual election was a bit of a walkover -- as Taft, benefiting from Roosevelt's popularity and endorsement, beat Jennings Bryan 321 electoral votes to 162.

Turnout declined steadily for, roughly, the next 50 years -- although it dipped below 50% of eligible voters only twice: in 1920 and 1924. (Those dips are explained by the hesitant participation of women in the elections after the 19th Amendment gave women the right to vote in May 1920.)

In 1960, however, turnout surged back to near-record levels with 63.8% of eligible voters turning out to choose between John F. Kennedy and Richard Nixon. Kennedy's candidacy excited Americans previously uninterested in politics, while Nixon was a known commodity as the sitting vice president. The race was also extremely close throughout, perhaps convincing people more than usual that their votes mattered.

The 1960 election was a one-off, though -- as turnout in presidential elections slumped in its wake. In advance of the 1976 presidential election -- in which just 54.8% of eligible voters cast a ballot, according to the United States Elections Project -- The New York Times' Robert Reinhold wrote of the declining interest of the average American in their elections. Here's the key bit:

"The facts are clear and startling. American voting participation, never very high compared with other democracies, has been declining steadily since 1960. In that year, 64 percent of the eligible voters turned out to give a razor‐thin edge to John Kennedy over Richard Nixon. Since then—even though literacy tests, poll taxes and many other impediments have been swept away, and despite vigorous registration drives—voting has continued to slip, dropping to 55 percent in the last Presidential election, the lowest since the roaring and complacent twenties. The decline also coincides with the increase of mass exposure, through television, to the political process, but no one seems to know what effect that has had on turnout...

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"...The 'alienation' theory holds that, after Vietnam and years of Watergate scandal and other political rot, the electorate is turned off, cynical, distrustful of government, uncertain that their votes make much difference."

Whatever the reason, turnout in presidential election continued to slide. In 1988, fewer than 53% of eligible voters actually voted, while as recently as the 2000 election that number was 54.2%.

Barack Obama's candidacy in 2008 led to the highest voter participation rate in recent memory -- 61.6% of eligible voters -- but that number dipped to 58.6% for his 2012 reelection race. And even with Hillary Clinton and Donald Trump -- two very well-known and uniquely divisive figures -- on the ballot in 2016, just 60.1% of eligible voters voted.

So why will 2020 be different?

Well, the 2018 midterm elections offer up some evidence that the electorate is very, very engaged. In Trump's first midterm election, 50% of eligible voters cast a ballot -- the highest percentage of participation in a midterm election since 1912 and a massive 13.3 percentage point increase from the dismal 36.7% turnout in the 2014 midterms.

What explains the surge? As Brookings senior fellow William Galston wrote earlier this year -- citing Pew polling data:

"Prior to the 2000 election between George W. Bush and Al Gore, just 50% of the voters thought that it really mattered who won, versus 44% who thought that things would be pretty much the same, whoever won. This year, a record 83%—including 85% of Democrats, 86% of Republicans—say that it really matters.

"Although divergent reactions to President Trump are driving some of this intensity, clashes on the issues are playing a role as well. Prior to the 2000 election, 51% of the voters believed that the major party candidates were articulating differing positions on the issues, compared to 33% who saw them as taking similar positions. This year, 86% perceive the candidates as differing on the issues, while only 9% see similarities."

In short: People believe now -- more than in recent memory -- that a) there are major differences between the two major parties and b) the identity (and party) of the election winner will have a profound effect on the future of the country.

There's little question, then, that turnout -- because of these feelings as well as a series of changes that make it far easier to vote by mail amid the coronavirus pandemic -- is going to be quite high. It seems likely to surpass the 61.6% participation rate in 2008. But could it get all the way to, say, 66% of eligible voters -- which would set a modern turnout record?

If turnout got to 65% -- just short of the record -- that would mean roughly 150 million ballots are cast, according to University of Florida professor Michael McDonald, who closely tracks turnout numbers with his US Elections Project. In 2016, by way of comparison, more than 133 million votes were cast.

The early vote numbers in 2020 are staggering. The real question is what turnout on November 3 actually looks like.

The biggest question is whether turnout on November 3 will break records -- but there's no question that it will be close.