2016 Election Forecast: Predict Which Candidate Will Win the Presidential Election

A candidate needs 270 electoral votes out of 538 to win the presidency. Get started to make your own forecast.

1.

5 Storylines to Watch Tonight

As millions of voters tune in to watch the first general election presidential debate of the 2016 campaign, there are several key factors to keep in mind. The general election has been playing out for about two months now, with Donald Trump and Hillary Clinton taking direct aim at one another, but tonight will be the first time that they square off directly. Here are the major storylines to watch, courtesy of ABC's MEGHAN KENEALLY: http://abcn.ws/2cEM3Fh

2.

The Impact of Debates? It's Debatable

Do these showdowns matter? The chances for impact seem ripe this year. The two most unpopular major-party candidates in the history of ABC News/Washington Post polls are facing off. Donald Trump's unorthodox campaign style and provocative positions have piqued public interest; the debates may be the single best opportunity for him to allay concerns about his qualifications, temperament and policy promises alike. Hillary Clinton, for her part, needs -- like Trump -- to ease questions about her trustworthiness, as well as to spark greater enthusiasm among her supporters. Can either candidate move the needle? It will be tough, ABC's GARY LANGER notes. A review of data since 1960 suggests that past debates have almost never directly and measurably changed the candidates' relative standings. That's admittedly a high standard, though, and at least some debates may have had more subtle impacts. http://abcn.ws/2daluGz

3.

What Gary Johnson Will Be Up To

When Clinton and Trump take the debate stage at Hofstra University tonight Gary Johnson will watching on television some 30 miles away in Twitter's Chelsea office in Manhattan -- armed only with a Twitter handle. The campaign is coordinating with Twitter to build out a robust social media strategy during the 90-minute debate. Both Johnson and his running mate, former Massachusetts Gov. Bill Weld, will be live-tweeting throughout the evening. More details from ABC's JORDYN PHELPS: http://abcn.ws/2d3rVMe

4.

Analysis - ABC's Rick Klein

What if he apologizes? What if he behaves himself? What if he drops "Crooked Hillary" for "Madam Secretary"? What if – stay with us here - he doesn't stretch the truth? Forget the no-holds-barred attacks Donald Trump has proven himself capable of. Hillary Clinton's worst nightmare might be humble Trump, since that would flip storylines enough to potentially dominate the takeaways regardless of what else happens at Hofstra. Clinton's camp is pressuring Lester Holt to do the fact-checking the candidate doesn't want to do by herself. But she may be in the position of wanting and needing to draw Trump out – to bait him into a discussion of President Obama's birth status, for instance, or a real policy discussion on Iraq or Afghanistan or ISIS. Clinton-as-aggressor would surely be unexpected. It also may be helpful in a race where she continues to struggle to lock down her base. The latest ABC News/Washington Post poll shows Trump getting a larger share of Republicans and of Romney voters than Clinton is of Democrats and Obama voters. Clinton isn't known for smackdowns. But it may not hurt for her to show some fight.

5.

By the Numbers -- Clinton-Trump Race Narrows

The race between Hillary Clinton and Donald Trump has narrowed to essentially a dead heat nationally, according to the latest ABC News/Washington Post poll, raising the stakes dramatically for the first presidential debate tonight. The debate is expected to have a huge audience -- 74 percent of Americans say they plan to watch. And while eight in 10 say the debate won't change their minds about who they will support, that leaves more than enough votes up for grabs to shift the balance in an increasingly tight contest. Voters have serious qualms about both candidates, polls show. Trump, in particular, is running competitively despite about six in 10 Americans continuing to see him as unqualified, untrustworthy, temperamentally unsuited and insufficiently knowledgeable of world affairs to serve effectively as president. Yet he’s capitalizing on the strength of his core groups of supporters and on Clinton’s own weaknesses, including concerns about her health. ABC's GARY LANGER has more. http://abcn.ws/2ctBNS1

6.

Mook: Clinton Shouldn’t Have to Spend Debate Correcting Trump's 'Lies'

Hillary Clinton's campaign manager Robby Mook said the campaign is concerned about a "double standard" at Monday night's debate where Donald Trump "lies" and still receives a "passing grade." "All that we're asking is that if Donald Trump lies, that it's pointed out," Mook said on ABC's "This Week." "It's unfair to ask that Hillary Clinton both play traffic cop with Trump, make sure that his lies are corrected, and also to present her vision for what she wants to do for the American people." ABC's JOSH HASKELL has more. http://abcn.ws/2cu7JR6

7.

Trump Campaign Calls Debate Moderator ‘Brilliant’

Donald Trump's campaign manager Kellyanne Conway on Sunday called the NBC Nightly News anchor who will preside over Monday night's presidential debate a "respected, brilliant newsman," a sharp change in tone for the campaign, which in recent days has claimed they don't feel Trump will be treated fairly in the debates. "He'll do a good job tomorrow night as a moderator," Conway said of Lester Holt. Trump this past week said Holt will be under tremendous pressure to be tough on the Republican presidential candidate and called him a Democrat when in fact Holt is a registered Republican, notes ABC's MARGARET CHADBOURN. In advance of Monday's event, the campaigns for Trump and Hillary Clinton have differed on whether Holt and the moderators of subsequent debates should fact-check the candidates or leave it to the candidates to challenge each other’s statements. http://abcn.ws/2djTRik

8.

Gennifer Flowers Not Invited to Attend Presidential Debate by Trump Campaign, Officials Say

Donald Trump's campaign manager, Kellyanne Conway, said yesterday that Gennifer Flowers has not been invited to the debate. Bill Clinton acknowledged in the late 1990s that he had a sexual relationship with Flowers in the late 1970s, and in a tweet on Sunday Trump appeared to threaten to bring her to the debate. "If dopey Mark Cuban of failed Benefactor fame wants to sit in the front row, perhaps I will put Gennifer Flowers right alongside of him!" Trump tweeted on Saturday. But in separate Sunday show appearances, both Conway and Trump's running mate, Indiana Gov. Mike Pence, indicated there is no plan for Flowers to be at the debate, ABC's MICHAEL FALCONE and JOSH HASKELL report. http://abcn.ws/2d1lglt

Best of the 2016 Primary Debates

Inside the Republican National Convention

Inside the Democratic National Convention

In Depth: The Latest ABC News-Washington Post Polls