In the campaign's final days, Donald Trump and Hillary Clinton are spending their time and money on key battleground states.

They're trying to reinforce support in states they must carry to collect the 270 electoral votes they need to win the presidency and making last-minute maneuvers to try to steal states from their rival.

As everyone waits to see how the revived Clinton inquiry affects the outcome, here's a look at the state of play in places that could make the difference.

Florida (29 electoral votes)

George W. Bush won 2000's contested race and had a bigger margin in 2004. Barack Obama won by 3 points in 2008 and just 1 point in 2012.

This is a state that Donald Trump must win.

In the past four elections, about 30.5 million presidential votes have been cast here, and the difference between Republicans and Democrats was 71,000 votes. No other state has been closer.

Hillary Clinton and Trump were tied in a Sept. 8 statewide poll, and things trended in Clinton's direction until the past few weeks, when they tilted to Trump — who owns property in the state.

Analysts say that the state's growing diversity could help Clinton, and she has made the state a key target for voter registration and organizational efforts.

But the GOP has recently dramatically improved its ground game. It has more than 1,000 trained staff and organizers across the state, compared with 84 in 2012.

A poll last week in Miami-Dade County, the state's most populous area, found Clinton outpacing Trump there by 30 points, even with the traditionally Republican Cuban voter base, many of whom are turned off by his anti-immigrant policies and rhetoric.

Ohio (18 electoral votes)

No Republican has won the White House without Ohio. Since 1944, voters here have sided with the loser once — Richard Nixon in 1960.

Ohio has long been considered a political bellwether state because its sentiments seem to often be reflective of the national mood.

It is older and whiter than most of the country; those voter groups have tended toward Donald Trump. But it has rebounded from the Great Recession more quickly than other Rust Belt states, making it less receptive to Trump's outreach to disaffected blue-collar workers.

Recent polls suggested that the Republican didn't take a big hit here after his treatment of women made headlines. Unlike many other states, the gender divide finds women almost evenly split: 48 percent support Trump and 45 percent back Hillary Clinton. Married women break for Trump, 54 to 40 percent.

Clinton's edge among college-educated whites is narrower here than elsewhere, with 48 percent supporting Clinton to 44 percent for Trump. And some recent surveys found that she was viewed less favorably than her rival.

Last-minute campaigning might not make a big difference here. A recent poll found that just 5 percent of likely voters were still undecided.

North Carolina (15 electoral votes)

Barack Obama reversed decades of GOP dominance to eke out a 2008 win. It was the second closest state in 2012 and went for Mitt Romney.

Early voting data showed that Democratic early turnout had remained steady, and Democratic women were casting early ballots in disproportionate numbers — 87,000 of them compared with 60,000 Republican women.

That helps explain why Hillary Clinton believes she has a good shot at winning this diverse and unpredictable state. Her support is bolstered by a 93-4 percent advantage among black voters.

Black voters turned out and cast their votes in 2012 for President Obama by a margin of more than 7 to 1, but it was not enough to win the state for him.

What makes North Carolina unique this year is the number of close races that could be affected by the outcome of the presidential battle. It's the only state in which races for president, U.S. Senate and governor have all been rated toss-ups by the Cook Political Report.

Another factor that makes the state hard to call: its balanced electorate. Forty percent of voters are registered Democrats, 30 percent are Republicans and 30 percent are unaffiliated.

Arizona (11 electoral votes)

Except for Bill Clinton's 1996 win, it has voted Republican in every presidential election since 1952. Democrat Harry Truman won in 1948.

Hillary Clinton dispatched high-profile surrogates Sen. Bernie Sanders, Chelsea Clinton and First Lady Michelle Obama to the state this month, verifying that Democrats think they have a real shot at carrying deep red Arizona.

Compare that to 2012, when President Obama steered clear of the state during his re-election campaign because he knew he had zero chance of winning. He was right: Republican Mitt Romney won by 10 percentage points.

What changed? The state's growing Latino population of about 2.1 million is the sixth largest in the U.S., and they comprise some 22 percent of eligible voters. Many of them are motivated to vote against Donald Trump because of his views on immigration and Mexico.

Republican Sen. John McCain, who is seeking re-election on Nov. 8 and was the GOP presidential nominee in 2008, has made his disdain for Trump very public and withdrew his support this month.

In September, the conservative Arizona Republic newspaper broke with tradition and endorsed a Democrat for president for the first time.

Colorado (Nine electoral votes)

George W. Bush won by 9 points in 2000, narrowly beat John Kerry in 2004. Then the state flipped, backing Barack Obama in 2008 and 2012.

As recently as 2004, the state was written off by Democrats. At that point, Republicans had carried it in eight of the previous nine presidential elections.

But Barack Obama won the state twice and its politics are changing, in part because of the rising influence of Latino voters.

There are other reasons the state might not be a good fit for Donald Trump: It has one of the youngest and most highly educated populations in the country. He has fared poorly among those groups. There's also little of the economic discontent that has fueled the Republican's support in the industrial Rust Belt.

However, there is one trend that might help Trump. Although there are more registered Democrats than Republicans — for the first time in 32 years — the state's fastest-growing political affiliation is unaffiliated, or independent, voters. They make up a plurality of the electorate, a distinction held by just five other states: Alaska, Arizona, Iowa, Maine and New Hampshire.

If independents break for Trump, Hillary Clinton's current narrow advantage could evaporate.

Nevada (Six electoral votes)

Republicans dominated through the late 1980s, but a population influx has made it a true battleground. Barack Obama won here twice.

Many voters live in remote — and conservative-leaning — parts of the state, which makes polling and discerning trends difficult. Polls, which are conducted in English, might not be picking up Latino preferences.

Because of the state's growing minority population and large unionized workforce, groups that lean Democratic, some analysts wonder why Hillary Clinton isn't way ahead. Recent polls suggest that reports of Donald Trump's inappropriate behavior toward women didn't deeply erode his support.

There is a wide gender gap in the state: Clinton leads by double digits among women; Trump's margin among men is about the same. Clinton performs somewhat better among younger voters, but she's nowhere near the level of support that Barack Obama had here.

The candidates' stances on issues might make the difference. Trump has a slim edge on handling the economy, but Clinton's policies are preferred on immigration and trade.

Most voters say Clinton has the better temperament for the office, but a sizable group say neither candidate shares their values.

Iowa (Six electoral votes)

Democratic presidential nominees have won here in five of the last six elections. The 1996 outcome wasn't close, but 2000 and 2004 were.

Demographics account for some of Donald Trump's appeal here. More than 60 percent of projected 2016 voters are whites without a college degree, a group that was a key source of his support through the primary season. The national average: 42 percent.

While Democrats have expanded their voter registration in other states, including Florida, Nevada and Colorado, Republicans have maintained their edge in Iowa, with a lead of almost 34,000 voters.

Polls suggest that both candidates have a loyal base of support, but as many as 4 in 10 voters have said that they will turn out to vote "against" a candidate, not for one. That could put a dent in turnout.

There's a gender gap here, too. Trump is ahead by 10 points or more among men, while Clinton has a similar lead among women.

Evangelicals — in a state where their support remains very important — are far more likely to support Trump than Clinton.

And here's something to consider: Clinton won the Iowa caucuses on Feb. 1, but Trump was defeated by Texas Sen. Ted Cruz.

New Hampshire (Four electoral votes)

Voters are independent and hard to predict, but the state has voted Democratic in five of the last six elections — barely in 2004 and 2000.

Socially liberal but fiscally conservative, the state that gave Donald Trump his first primary victory is a frequent destination for him. The mostly white voter base might not be an ideal target for him because it is more educated than in other states, but registered Republicans outnumber Democrats by about 24,000 votes.

While manufacturing losses have hurt the economy, white-collar jobs have taken the sector's place. The state currently has the nation's second lowest unemployment rate at 2.9 percent. The jobs crisis in other states that has fueled support for Trump might not be a factor here.

Hillary Clinton's biggest concern could be that younger Democrats who picked Sen. Bernie Sanders over her in the party's primary election might stay home. That's why the duo has campaigned together here. One issue that could woo Sanders supporters to her side is college affordability; residents have the nation's largest student debt burdens.

A wild card: Libertarian candidate Gary Johnson is doing well here among the 18-45 voting bloc and has 10 percent support overall.