A wild election is coming to a close — and no one is sure how it will end

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How much could possibly happen in such a short period of time?

The month between the first presidential debate and the Democratic National Convention was arguably the most jaw-dropping in modern U.S. politics — from President Biden’s disastrous debate performance to an assassination attempt on former President Donald Trump to Biden dropping out soon after the Republicans’ convention and Vice President Harris quickly consolidating support among Democrats.

For the better part of a year, perhaps more, this was a race between two very well-known candidates: Trump and Biden. But Harris’ entrance upended all that. Enthusiasm among Democrats went through the roof, in part based on relief that Biden was no longer running and the idea that they had a fresh start.

Related: Get live election results and full coverage from OPB here

But after a relentless last month of attacks from Trump, his campaign and outside groups supporting him, the race has tightened, according to the polls. Democratic strategists are concerned that if the polling errors from 2016 and 2020 repeat, Trump will win — possibly easily.

There were polling errors in 2022 as well, but those underestimated Democrats’ support rather than Republicans’. Trump, of course, wasn’t on the ballot in the midterms, and his most ardent supporters tend to show up in much bigger numbers when he is.

No one knows what exactly will happen. More than 70 million people have already voted early, and more than double that are likely left to be cast and counted. If the states are as close as expected, a winner might not be declared for days. In 2020, the Associated Press, whom NPR follows for calls, didn’t make its call until the Saturday after Election Day.

In that void before a race call, Trump will likely declare victory and cry fraud. He’s essentially done that for four years, and it’s what he’s been setting the stage for in the closing days of the campaign.

The uncertainty reflects a consequential election, not just for the president, but also for who controls Congress.

Republicans are favored to win the Senate, while the House is up for grabs

A president without full control of Washington’s political levers has almost no chance of passing major legislation, so the outcomes of the White House, Senate and House are all pivotal.

Related: Inside Oregon's tightest congressional race

Democrats are facing one of the worst Senate maps for a party in modern political history. Republicans are expected to win control of the chamber and need to win just two seats if they lose the White House and one if Trump wins (because a vice president would break ties). Republicans are already favored to flip two seats — in West Virginia and Montana, according to the Cook Political Report.

There are half a dozen more competitive seats that could mirror how the presidential election goes in those states, including Ohio, Wisconsin, Michigan, Pennsylvania and Nevada. Democrats are hoping to make Texas and Florida competitive, but those are reaches.

How many Senate seats Republicans pick up could be critical to how long Democrats are in the minority — and if they have a shot at winning back the chamber two years from now.

There are fewer competitive House seats this year than almost ever before because of redistricting and members of Congress wanting to insulate themselves from difficult and expensive races, but Democrats’ chances of retaking the House have improved in the past month, according to forecasters like Inside Elections.

Related: Gluesenkamp Perez, Kent locked in another tight congressional race in Southwest Washington

For control, Democrats need a net gain of four seats. Inside Elections sees a possible range of Democrats winning a net of nine seats to a Republican net pick up of one. So Democrats have a slight advantage for the first time this cycle.

It would be unusual for the House and Senate to go in opposite directions, especially in a presidential year. It has happened, though. Four times since 1934, a winning presidential candidate’s party lost seats in the Senate and gained in the House, but it hasn’t happened since 1984.

In that same time frame, the losing party in the presidential election twice gained in the House but shed Senate seats. In fact, Republicans did exactly that in 2020, gaining 13 House seats, but losing three in the Senate when Biden won the White House.

In the presidential election, who most represents “change” could be a deciding factor

Change is a powerful force in politics, but Americans appear split on which candidate most represents change in this election, according to pre-election polling.

Trump has the advantage of not being president during a time when people are pessimistic about prices, immigration and America’s foreign policy.

Harris is the sitting vice president, but she represents change for a lot of people in part because she’s younger than Biden and she’s not Trump; she would also be the first woman, first Black woman and first person of South Asian descent to be president.

Americans are in a bad mood — and have been for some time

Winning the mantle of “change” is especially important when people are so pessimistic about the direction of the country.

Every month for the last 15 years, Americans have said the country is off on the wrong track. That has had a profound effect on U.S. elections. People are more jaded about politics — and its effectiveness — than ever before.

Related: OPB polled Millennial and Gen Z Oregon voters. They aren't happy

Americans have near-record-low trust in government and its institutions, including health agencies, law enforcement, the Supreme Court and the media.

It’s happening at a time when Americans are also more sorted socially and politically — in the neighborhoods they live in and in the information they consume. “Place,” where someone lives, may be even more determinative than race, gender and ethnic identity in how people vote.

Voters in both parties see threats from the other side to their way of life and to what it means to be American. Conservatives see a culture that is too liberal, weak and enabling. They see a country whose best days are behind it and whose culture and way of life has worsened since the 1950s.

People on the left, on the other hand, see the rights of women, the marginalized and democracy itself as under threat because of leaders who have given license to intolerance and conspiracy.

When people are in a bad mood, they tend to blame those in charge, and that’s certainly been the case on the economy and immigration. Despite strong signs of economic recovery since the pandemic, Americans are feeling the pinch of higher-than-pre-pandemic grocery prices and interest rates. The cost of living has gone up and housing is less affordable.

Many Americans are also concerned about the number of migrants crossing the southern U.S. border. All of that has presented challenges for Harris — as it did for Biden before her. It’s led to a distinct advantage for Trump on those two issues.

Harris, on the other hand, holds a larger advantage on women’s reproductive rights, and the gender gap in this election could be the widest in U.S. history.

Trump faces significant challenges on character

Trump has upended American politics in the last decade. Things that Republicans would have never pressed for in decades past, Trump has convinced his followers is the right path forward: less intervention overseas; a reduced commitment to allies; more trade barriers; a softer line toward Russia; praise for dictators and strong men.

His inflammatory rhetoric and race-based grievances have polarized the country. Views of Trump have changed little since he’s come on the political scene. For years, more than half the country has said they have an unfavorable opinion of him.

But he has a loyal — and seemingly immovable — base of support. He has what’s known in politics as “a high floor and a low ceiling.” He got roughly 46% of the vote in 2016 when he won, and 47% of the vote in 2020 when he lost.

His presence in GOP politics has meant that anyone wanting a party nomination for almost any office has to get his blessing, but the negative views of him among many suburban and swing voters has resulted in Republican losses in election cycle after election cycle.

He lost the popular vote by 3 million votes in 2016 and by 7 million in 2020. It’s possible that Trump wins this year and becomes the first person to win twice while losing the popular vote twice. (He could win the popular vote this time, though, given that Harris’ leads in national polls are much smaller than Hillary Clinton in 2016 or Biden in 2020.)

Because of the Electoral College — and the swing states being more conservative than the country at large with higher percentages of Republican-leaning white voters without college degrees, especially in the Blue Wall states of Wisconsin, Michigan and Pennsylvania — Trump was able to win in 2016 and only narrowly lose in 2020 by just tens of thousands of votes.

This election is expected again to be very close and decided by just a handful of states. In addition to those Blue Wall states, four Sun Belt states are the big focus: North Carolina, Georgia, Arizona and Nevada. The reality of the map is that Trump can’t win without winning one of the Blue Wall states, and Harris can’t win without winning one of Pennsylvania, North Carolina or Georgia.

The intersection between their paths is Pennsylvania, which explains why the campaigns have spent $600 million on political ads to try and win there since the beginning of the 2024 cycle. A whopping $1.2 billion has been spent in the state on ads with all races combined, including for Senate, House and farther down ballot. It’s the most money ever spent on one single state.

Polarization won’t end with election night

Harris has tried to make Trump’s words and actions a part of her own messaging this campaign — to remind voters of what she considers to be a threat to democracy.

While that may persuade the moderate Republicans she’s been courting, Trump’s base is locked in, despite his unsubstantiated claims that criminal charges against him are politically motivated, or his insistence that the 2020 election was stolen, a lie that helped fuel the violent siege at the U.S. Capitol on Jan. 6, 2021.

Republicans now are more likely to say the country needs a “strong leader,” compared to Democrats, who say it’s most important to have a leader who is “honest and trustworthy,” according to a recent NPR/PBS News/Marist poll.

Republicans are also more likely to say the country needs a leader who breaks rules to set things right, and 1 in 3 believe “patriots may have to resort to violence in order to save our country.” That has only increased since the Jan. 6 attack.

All of that has meant a divisive and polarizing presidential election that could go either way — and a post-election period that has many concerned about the way forward, especially when the integrity of U.S. elections has been what has set the country apart from other countries around the world.