The preliminary numbers appear to show Clinton, the Democratic presidential nominee, with an edge in several of the roughly 10 battleground states that would decide the 2016 White House race.
“We’re seeing eye-popping vote-by-mail application numbers,” Clinton campaign manager Robby Mook said on “Fox News Sunday.”
In Arizona and North Carolina, for example, more registered Democrats than Republicans have indeed cast early ballots.
But such numbers are open to interpretation, including how many Democrats in those two states voted for Clinton.
Meanwhile, early data shows Republican presidential nominee Donald Trump with potential advantages of his own in battleground states Florida, Ohio and elsewhere.
Only some of the 37 states that allowed early voting made public the number of registered Democrats and Republicans who requested early ballots and voted early.
So, final numbers won’t be known until Election Day on Nov 8.
Still, the Clinton campaign seemed bolstered in recent days by mail-in balloting in battleground Florida, where in-person voting started Monday in a majority of counties.
Early Florida numbers showed about an equal number of Democrats and Republicans had requested a record 3.1 million early ballots, compared with 2008 when Republicans led 49-to-32% and President Obama still won the state.
However, registered Republicans now have a slight lead – 1.8 percentage points – in the nearly a million ballots received by last Friday.
Trump, on a swing through Florida on Monday, made another push for supporters to cast their votes now.
“You got to get out there. Who’s voted already?” Trump asked a cheering crowd in St. Augustine. “If you’re not feeling well on Nov 8, we don’t want to take a chance.”
Clinton said in battleground North Carolina on Sunday: “From now until Nov 5, you can vote early. It’s a big deal. You get to vote today, right after this event.”
Mook also pointed out on Sunday that in Nevada, officials saw a “record turnout” in Democratic stronghold Clark County, which includes Las Vegas.
However, Trump has throughout the campaign appeared to have the support of some potential crossover voters, including Latino immigrants who back his tough message on illegal immigration.
A recent CNN/ORC poll, for example, found 33 percent of registered Latino voters in Nevada support Trump, compared to 54% for Clinton.
The Clinton campaign declined Monday to provide details on the states to which Mook and vice-presidential nominee Tim Kaine referred Sunday.
Kaine told NBC’s “Meet the Press” that the campaign “like(s) the early voting activity and the absentee-ballot requests coming in.”
Kendra Stewart, College of Charleston political science professor, said Monday that Kaine and Mook are “doing exactly what they should be doing by trying to use this as an opportunity to create enthusiasm within the party in the hopes of a bandwagon effect.”
However, she cautioned about the effort perhaps “leaving some Democratic voters less motivated to vote if they feel like their candidate doesn’t really need them” and giving the Trump campaign the opportunity to use the underdog strategy to try to rally supporters to get out and vote.
Elliott Fullmer, a Randolph-Macon College political science professor, suggested either camp could play up select early-vote trends.
“I don’t think it would be a surprise for a campaign to think any positive momentum would play well,” Fullmer said Monday. “And the more they can discuss an advantage in early voting, they will.”
According to the University of Florida’s US Elections Project, roughly 6 million Americans have already cast early votes, which do not include absentee ballots.
More than 46 million people are expected to vote before Election Day – or as much as 40% of all votes cast.
The District of Columbia also allows early voting.
Included in the 37 states that allow early voting are Colorado, Oregon and Washington, which have only mail-in balloting.
Clinton holds a 6 percentage point lead over Trump in national polls, according to the RealClearPolitcs average.
Clinton – who has been the frontrunner for the entire race – also has leads in battlegrounds states New Hampshire, Pennsylvania and Virginia.
Trump leads in battlegrounds
Though neither Georgia nor Ohio break down early balloting by party affiliation, Trump appears to have an advantage in both states.
In Ohio, such requests are down 10 percent among black voters, who in recent decades have tended to vote for Democrats. And requests among Ohio’s increasing white population, a voting bloc in which Trump appears to do well, is up 3 percentage points, to 91%.
In Georgia, ballot requests and returns among black voters trail 2012 levels.