American voters will head to the polls one year from Sunday to elect their next president.
Before they get there, they'll be put through a throttling.
A historic impeachment battle against President Donald Trump is timed to coincide with a Supreme Court term apparently destined to dredge up top social flashpoints, from abortion to guns to immigration.
In addition, President Barack Obama's signature policy initiative will face its latest test in a legal challenge that could affect the health care of millions of Americans and disrupt one of the country's largest economic sectors.
And, of course, these are the events that we know are going to happen. As with every presidential race, the potential for significant surprises looms.
Political scientists caution that events such as these rarely tilt the balance in presidential races, which often come down to the so-called fundamentals, such as the health of the economy and the approval rating of the incumbent.
But this time might be different. There have only been two impeachments in American history. On top of that, polarization has reached historic highs, a potential wrench in traditional understandings of what will motivate Republicans and Democrats to participate in the political process.
Here are some of the key political events coming down the pike that could shape the battle for the presidency.
With barely any previous experience with impeachment, election analysts have struggled to gauge how it might impact the presidential race.
"We don't really have any historical precedent because the last two times impeachment was on the table it was for Nixon and Clinton and they were both in their second terms," said Kyle Kondik, a leading elections analyst at the University of Virginia Center for Politics and author of "The Bellwether: Why Ohio Picks the President."
Washington expects that Trump, like Andrew Johnson and Bill Clinton before him, will likely be impeached by the House of Representatives and then acquitted by the Senate, which has a Republican majority.
But that legal victory might become an electoral setback, according to Rachel Bitecofer, assistant director of the Wason Center for Public Policy at Christopher Newport University. Bitecofer said she is using the contentious confirmation battle of Supreme Court Justice Brett Kavanaugh shortly ahead of the 2018 midterm elections as a guide.
"There's a misperception that in the 2018 election, the Kavanaugh fight ended up helping Republicans," Bitecofer said. Based on her research, Kavanaugh's confirmation was actually more likely to motivate Democrats to vote, she said.
"My expectation is that if Trump is acquitted, that Republicans will not be the beneficiaries of that," she said.
Kondik suggested that even if there's an acquittal, the details of the Senate vote could matter.
"Certainly the president would claim vindication. The Democrats would say he was saved by his own party," he said. If there are Democrats who also vote to acquit, it could bolster the president's case, he added.
The timeline for impeachment is not set in stone, though the process is moving quickly in the House. It is possible that a formal impeachment vote could be taken by the end of the year, and Senate Majority Leader Mitch McConnell has indicated that he intends for the trial to be swift. On Thursday, the House passed a resolution establishing rules for the public phase of the inquiry by a nearly party line vote of 232-196.
The first president to be impeached, Johnson, was not elected to a second term after failing to win his party's nomination in 1868. The second, Clinton, saw his approval rating hit new highs after the proceedings started. Trump's approval rating sits in the low 40s, and has proven to be unusually steady despite the frenetic pace of events in Washington.
The Supreme Court returned in October with gusto, following up on a relatively quiet 2018 term, apparently determined to take cases concerning all of the nation's most divisive social issues.
The court will deliver rulings in the coming months on disputes involving abortion, guns, immigration, racial discrimination and LGBT rights. It is a "momentous" term, according to David Cole, national legal director of the ACLU.
On top of these top cases, a federal appeals court is weighing a Trump-backed challenge to eliminate the Affordable Care Act, also known as Obamacare. A decision in that case is expected any day, while the Supreme Court generally decides its most important cases in June.
Bitecofer described the cases in the pipeline as "ticking time bombs," primed to disrupt the election.
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Kondik said that the one with the potential to matter most is the health-care decision.
"Particularly if the courts blow a hole in the ACA, I think that would put Republicans at a disadvantage," he said. "They instigated blowing a hole in the ACA, and they don't have a way to fix it"
Peter Enns, executive director of the Roper Center for Public Opinion Research at Cornell University, said court cases can focus attention on a particular issue. Given the effect that the 2016 race was decided by razor-thin margins, that could be influential, he said.
"If in one particular area, abortion, becomes salient and that drives turnout — anything can swing a close election," Enns said.
But Enns said the cases over social issues are likely to have a far more muted impact than any potential Supreme Court case that touches on the president himself.
A case in which the Manhattan district attorney has sought the president's tax returns would have the most impact, he said. The case is now before a federal appeals panel in New York.
"The net effect I would predict to be negative and harder to defend in 2020 than in 2016," Enns said.
In the 2016 race, it was a letter from then-FBI Director James Comey notifying lawmakers that he was taking new investigative steps in the probe of Democratic nominee Hillary Clinton's email use.
In 2020, it could be anything. Experts say that among the candidates for a last-minute surprise, a Supreme Court vacancy is the one that could matter most, absent issues of war and peace.
"That would be the most disruptive type of thing that could possibly happen," Bitecofer said.
Kondik said that Justice Antonin Scalia's death in 2016 solidified support for Trump, who earned votes from Republicans who were not otherwise supportive of him.
"It raised the political cost of crossing over to vote against the Republican nominee," Kondik said.
Both Democratic and Republican strategists are preparing for a potential vacancy on the court, CNBC has reported. If a vacancy opens up next year, McConnell has pledged to attempt to fill the seat, despite the fact that he opposed Obama's 2016 nominee Merrick Garland because it was an election year.
Overall, analysts say that events are less likely to have an impact in shaping the 2020 election than in previous cycles because voters have become so polarized.
Bitecofer said that one of the consequences of polarization is that "vote choice is nearly 100% predicable by partisan lean," meaning that events can't generally drive electoral outcomes.
Even the identity of the eventual Democratic nominee will not be that significant, she said, outside of the impact it has on driving turnout among certain demographics.
Kondik agreed, noting that the "floor" for both the Republican and Democratic nominees will be higher than they have been in decades, simply as a result of partisanship.
"With an electorate that is not as persuadable as past electorates, things that may seem like game changers at the time may not actually be," Kondik said.
This is the first of two stories taking stock of the year to come before Election Day 2020. The second, to examine economic issues, will be published Sunday.