Hillary Clinton gaining ground in key states
Hillary Clinton appears to be displaying strength in the crucial battleground states of North Carolina and Florida among voters casting ballots before Election Day, and may also be building an early vote advantage in Arizona and Colorado.
Donald Trump, meanwhile, appears to be holding ground in Ohio, Iowa and Georgia, according to data compiled by The Associated Press. Those are important states for Mr Trump, but not sufficient for him to win the presidency if he loses states like Florida or North Carolina.
"The Trump campaign should be concerned," said Scott Tranter, co-founder of Optimus, a Republican data analytics firm. His firm's analysis suggests a "strong final showing for the Clinton campaign" in early voting.
Early voting - by mail or at polling stations - is off to a fast start. More than 4.4 million votes have been cast already, far outpacing the rate for this period in 2012. Balloting is under way in 34 out of 37 early-voting states.
In all, more than 45 million people are expected to vote before Election Day - or as much as 40% of all votes cast.
Both parties are encouraging their supporters to vote early. The outcome of those ballots won't be known until counting begins after polls close on November 8, but some clues are available. Some states report the party affiliations of early voters, as well as breakdowns by race and gender.
The data that is available represents a small sample of the more than 120 million people who will cast ballots in the presidential election, but a notable one.
A look at early voting trends:
:: CLINTON: FLORIDA, NORTH CAROLINA, MAINE
The Clinton campaign is looking to build an insurmountable lead in Florida and North Carolina during early voting. If she wins either of those states, she'll probably be the next president.
Using 2012 as a guidepost, she appears to be in a strong position in early voting.
While Democrats tend to do better in early voting, Republicans usually post an initial lead with mail-in ballots before Democrats surpass them during in-person early voting in mid to late October.
Democrats so far have kept it close with mail-in ballots, giving Mrs Clinton a chance to run up the score with in-person early voting. To do that, she'll need non-whites and young people to turn out near the high levels they did in 2012 for Barack Obama.
In North Carolina, Democrats have moved ahead of Republicans in early voting. Republicans had held a modest lead based on mail-in ballots returned, but that was at a much narrower margin than in 2012, when Mitt Romney narrowly won the state. After in-person voting began on Thursday, Democrats overtook Republicans in overall votes cast.
In Florida, a record 3.1 million people have requested ballots, more than one-third of the total voters in 2012. Democrats have requested almost as many ballots as Republicans: 39% vs. 40%.
By comparison, in 2008, Republicans held a lead of 49% to 32% in requests, according to an analysis for AP by Catalist, a Democratic analytical firm. Obama won in Florida in 2008 and 2012.
Democrats are also showing momentum in the 2nd congressional district of both Maine and Nebraska. The two states allocate electoral votes by congressional district.
:: SIGNS OF EARLY EDGE FOR CLINTON OUT WEST
Early voting is surging in Arizona, another state Mr Trump can't afford to lose. Arizona has long been reliably Republican, but Mrs Clinton is targeting it.
More than 1.9 million ballots have been requested and 36,000 returned. That's more than triple the 10,800 ballots returned during a similar period in 2012.
Democrats have a 44% to 31% lead over Republicans in ballots returned. Another 25% were independent or unknown. At this point in 2012, Democrats had a narrower 38% to 35% lead, according to Catalist.
In Colorado, which began voting by mail on Monday, Democrats led 43% to 30% among the 15,280 ballots returned by late Thursday. In 2012, the party had trailed Republicans early. Registered Democrats have since surpassed Republicans in the state.
And in Nevada, which also began absentee voting this week, overall ballot requests and returns were down. There were sharper declines among older whites, who tend to vote Republican.
:: GOOD SIGNS FOR TRUMP: OHIO, IOWA AND GEORGIA
Early vote data for now points to potential Trump strength in Ohio, Iowa and Georgia.
In Ohio, data compiled by Michael McDonald, a University of Florida professor who runs the US Elections Project, continue to show big declines in ballot requests in the heavily Democratic counties of Cuyahoga and Franklin.
The state does not break down ballots by party affiliation. By race, voter modeling by Catalist found the white share of Ohio ballot requests was up, to 9% from 88%. The black share declined from 10% to 7%.
In Georgia, which also does not report party affiliation, both ballot requests and returns from black voters also trailed 2012 levels.
And in Iowa, Democrats lead early requests, 43% to 36%. But that level is down significantly from 2012. Obama won the state that year based on a strong early vote in his favour.
In a statement, the Republican National Committee said it was focused on boosting turnout in 11 battleground states and predicted a strong Election Day performance.
"Democrats are not turning out new voters, just turning out people who would have voted on Election Day," it said.