Below is analysis of CNN's 2018 national exit polls.
Voters in key states trust Republicans to protect pre-existing conditions
Health care was front and center in the 2018 midterm elections, with Democrats accusing their GOP rivals of undermining Obamacare's protections for those with pre-existing conditions.
Nationally, voters clearly felt the Democrats would better defend those who are or have been sick. Some 58% said Democrats would better protect health care for those with pre-existing conditions, compared to 34% who said Republicans would.
But voters in several key Senate races were more willing to trust Republicans with these popular Affordable Care Act provisions -- even though in some cases, the GOP candidates actively supported dismantling the landmark health care law.
Take Indiana, where Mike Braun defeated incumbent Sen. Joe Donnelly. Hoosier State voters had equal confidence in Democrats and Republicans when it came to protecting those with pre-existing conditions.
Same thing happened in Missouri, where Josh Hawley bested incumbent Sen. Claire McCaskill. Hawley is among the attorneys general who have filed a lawsuit in Texas District Court seeking to overturn the Affordable Care Act, including its protections.
When it came to Trump's economic and immigration policies, voters in states sending Republicans to the Senate had more positive views than the national electorate. For instance, they generally felt their financial situations had improved from two years ago. And fewer felt the president's immigration measures were too tough.
1:42 a.m. ET / Tami Luhby
Who abandoned the incumbent Democratic senators in Indiana and Florida?
Republicans will keep control of the US Senate in large part because Democratic incumbents running in states won by President Donald Trump lost support among key groups that have backed the President. And this helped cost senators like Indiana's Joe Donnelly their jobs. Donnelly succumbed on Tuesday to Republican challenger Mike Braun.
Compared to his first election in 2012, Donnelly lost the backing of men, those without college degrees and those making less than $50,000, in particular, according to preliminary results from CNN's national exit poll.
Donnelly saw his support among men slide 6 percentage points. He also saw a slide of 12 percentage points among those without college degrees and 11 percentage points among those making less than $50,000.
Indiana voters skewed red this year, with more approving of President Donald Trump than the general electorate.
Meanwhile, in Florida, Sen. Bill Nelson, another incumbent Democrat, was trailing challenger Republican Rick Scott and the race remained tight hours after polls closed. Regardless of the end-result, tonight's performance is a far different story for Nelson than 2012, when he won more than 55% of the vote.
Compared to 2012, Nelson's backing among those over age 45 dropped 7 percentage points. It dropped 9 percentage points among men, 7 percentage points among whites and 8 percentage points among those without college degrees.
Just over a majority of Florida voters approved of Trump, more than the electorate as a whole.
10:45 p.m. ET / Tami Luhby
Young voters support the Democratic candidate in higher numbers than last midterm
Preliminary CNN exit polls show voters between the ages of 18-29 reported supporting a Democratic candidate in the race for the House in higher numbers than in 2014. In the last midterm election, 54% of 18-29-year-olds voted Democratic while more than two-thirds said they voted for the Democrat so far in 2018.
While all age groups have supported a Democratic candidate in higher numbers than the previous midterm election, according to the early exit polling, the jump among the youngest voters is around 14 percentage points while those in other age groups moved up less than 10 percentage points.
9:24 p.m. ET / Grace Sparks
Most say Russia investigation is politically motivated
Slightly over half of voters in the 2018 election said that the investigation into Russian interference in the 2016 election is politically motivated, according to preliminary results from CNN's national exit poll. Around 40% said that it's a justified investigation. President Donald Trump often refers to the investigation as a smear campaign and "witch hunt."
Around the same number who think the investigation is justified, about 40%, approve of the job Robert Mueller is doing handling the investigation, while slightly more disapprove of his job.
8:14 p.m. ET / Grace Sparks
Americans more worried about voters being blocked from casting ballots
President Donald Trump has repeatedly raised the specter of voter fraud, warning as recently as Monday that law enforcement will be watching closely for any illegal voting.
"Law Enforcement has been strongly notified to watch closely for any ILLEGAL VOTING which may take place in Tuesday's Election (or Early Voting). Anyone caught will be subject to the Maximum Criminal Penalties allowed by law. Thank you!" Trump tweeted.
That's not in step with what worries Americans, however. More than half of voters said they were more concerned that people who should be able to vote will be prevented from doing so, according to preliminary results from CNN's national exit poll.
Just over a third said they were more concerned that people who shouldn't be able to vote will cast ballots.
Precincts in a multitude of states extended hours today because of voting issues.
When it comes to foreign interference, half of voters said they don't think the government has done enough to protect this election, while just over one-third said enough has been done.
8:08 p.m. ET / Tami Luhby
Voters didn't support Kavanaugh's appointment to the Supreme Court
Almost half of voters opposed Brett Kavanaugh's confirmation to the Supreme Court, according to preliminary data from CNN's national exit polls. A little over 40% supported his appointment. Around half of men supported Kavanaugh's confirmation compared to fewer than 40% of women who voted in this election, a significant gender divide.
On Roe v. Wade, two-thirds of 2018 voters said they would like to keep the landmark Supreme Court decision in place while only a quarter want it overturned. More than 80% said that sexual harassment is a very or somewhat serious problem in our country today and almost half said it's very serious.
7:43 p.m. ET / Grace Sparks
Higher support for Trump in some key states
In Indiana, around half of voters approve of the job Trump is doing as President around the same as in Missouri, slightly higher than the nationwide average. Both states feature tight Senate races where Democrats are trying to hold on to seats in states Trump won in 2016.
Voters in Indiana and Missouri are split between whether their vote for Senate was in support of the President, opposition, or whether Trump isn't a factor in their vote. Around a third in both states said that their Senate vote was in opposition to Trump while around three-in-ten said it was in support of him or Trump wasn't a factor.
7:38 p.m. ET / Grace Sparks
Mixed views of Trump's agenda
The election was very much about President Donald Trump, as many voters cast their ballot specifically to oppose or support him. Similarly, reviews of his agenda and his accomplishments were mixed. About half of voters said that Trump's immigration policies are too tough, while around a third think they're just right and few, only about 15%, think he's not tough enough, according to preliminary results from CNN's national exit polls.
The tax law passed by Republicans and touted by Trump hasn't had a lot of impact on American voters' personal finances, according to the poll. Close to half say they've seen no impact, while around three-in-10 said the law has helped and a quarter report the tax law has hurt them.
For his trade policies, which include new tariffs imposed on foreign countries and an update to NAFTA, about a third say they've had no impact on the economy in their area, but about 30% said that his trade policies have hurt them. A quarter indicate that his trade policies have helped their area's economy.
6:34 p.m. ET / Grace Sparks
Extremist violence was a factor in many votes in 2018
Around three-quarters said that extremist violence is an important factor in their vote for the US House in 2018, according to preliminary CNN exit data, with a quarter who said it's the most important factor and half who said it's an important factor. Few said that extremist violence is a minor or not a factor to their vote.
Another three-quarters of 2018 voters said that Americans are becoming more divided politically. Fewer than one-in-10 think the country is becoming more united, and slightly more say the country is staying about the same.
6:20 p.m. ET / Grace Sparks
Voters want more women and racial minorities elected to public office
Almost 80% of voters said that it's very or somewhat important that more women be elected to public office and almost half said it's very important. Slightly more women than men placed a priority on electing more women to public office, but not by much.
Slightly fewer but around seven-in-ten said that it's very or somewhat important for racial and ethnic minorities to be elected to public office. Around two-thirds of white voters said it's important to elect more minorities while around 80% of African Americans agreed.
6:17 p.m. ET / Grace Sparks
Most voters, particularly Democratic voters, want major changes in health care
It's no surprise that health care was the top issue for most voters. Roughly four in 10 voters listed it as their top concern, according to preliminary results from CNN's national exit poll.
This was especially true among Democrats.
What is more surprising is that roughly seven in 10 voters said they wanted major changes to the nation's health care system, with more Democrats feeling this way than Republicans. Among voters who felt that health care needs minor, more were Republicans. More Democrats wanted no changes.
This is a huge swing from two years ago, when President Donald Trump and congressional Republicans saw their big wins at the polls as a mandate to repeal the Affordable Care Act. The effort ultimately failed, though the Trump administration continues to undermine the landmark health reform law through regulatory changes.
This election, however, revolved around retaining Obamacare's key provisions that protect those with pre-existing conditions. Democratic candidates repeatedly attacked their Republican rivals as jeopardizing the health insurance of millions of Americans who are or have been sick. The popularity of these Obamacare protections forced Republican candidates to promise to uphold these measures.
Many voters weren't convinced. More than half said Democrats would better protect health care for people with pre-existing conditions, while only one-third said Republicans would.
6:03 p.m. ET / Tami Luhby
Correction: This post has been updated to reflect it was more Republicans and not a majority of Republicans who support minor changes and more Democrats support no changes to the health care law.
Nancy Pelosi more unpopular than Donald Trump
The Democratic Party has slightly higher favorability than the Republican Party in preliminary data from CNN's national exit poll. About half of voters said they had a positive view of the Democratic Party, while the Republican Party is upside down, with slightly more than 40% saying they had a positive view of the Republicans.
The downside for Democrats is an extremely low favorable rating for Nancy Pelosi, the woman who would like to again be Speaker of the House if Democrats win control of the House of Representatives. Only about three-in-10 voters had a positive view of Pelosi and more than half had an unfavorable view. In fact, more voters had an unfavorable view of Pelosi than had an unfavorable view of President Trump, according to preliminary results.
-- 5:56 p.m. ET / Grace Sparks