WASHINGTON — On the biggest day of voting since the coronavirus disrupted public life, Americans cast ballots in extraordinary circumstances on Tuesday, heading to the polls during a national health and economic crisis and amid the widespread protests and police deployments that have disrupted communities across the nation.
It made for some unusual scenes in this most unusual election season.
In the nation’s capital, for instance, polling places are open until 8 p.m., while the citywide curfew in place begins at 7 p.m. (the police did not anticipate arresting voters who broke the curfew).
In Philadelphia, 70 percent of polling places were closed while the authorities banned vehicle traffic and shut down public transportation in Center City, the downtown area, because of the unrest, meaning the only ways to get to polling sites were by foot or by bicycle.
And in Indianapolis, where 90 percent of polling locations were closed, voters faced long lines outdoors in 90-degree heat to vote in the remaining spots.
The voting also came amid a sustained assault on the electoral system by President Trump, who has falsely attacked mail voting as biased toward Democrats, threatened to withhold federal resources from states that mailed ballots to voters and suggested in general, with no evidence, the Democrats are looking to rig the election.
Voters in eight states and Washington, D.C., were choosing nominees for congressional and local offices while casting perfunctory primary ballots in the presidential contest, which has long been set between Mr. Trump and former Vice President Joseph R. Biden Jr.
The most prominent down-ballot race on Tuesday involved Representative Steve King of Iowa. Ostracized by his party after giving an interview questioning why white supremacy was considered offensive, Mr. King, a nine-term Republican, faced the toughest primary of his career.
Elsewhere, Valerie Plame, the former C.I.A. agent outed in what became one of the biggest scandals of the George W. Bush administration, was seeking the Democratic nomination for a House seat in New Mexico. Iowa Democrats were choosing a nominee to face Senator Joni Ernst in the fall. And Republicans in an open Indiana House district sold themselves as Trump allies in a seat Democrats hope to flip in November.
The impact of current events was evident in Philadelphia, where voters were confronted with the dual realities of going to the polls in a city shaken by confrontations between police and protesters. Activists were also concerned about the presence of police officers and National Guard members near polling places, which they said might intimidate some voters.
“We are seeing and feeling the effects of the police response to the protests over the last few days,” said Suzanne Almeida, interim executive director of Common Cause Pennsylvania. She cited the city convention center, where 18 polling locations had been condensed into one, as having a significant presence of National Guard troops, “which is obviously a deterrent to voters.”
Voters reported wait times of 90 minutes to two hours at Finley Recreation Center and Anna B. Day School in the East Mount Airy neighborhood of Philadelphia.
And counties across Pennsylvania were swamped by a surge in absentee ballot requests. On Monday night, Gov. Tom Wolf ordered six counties to keep counting ballots that arrived after Election Day for up to seven days, as long as they were postmarked by 8 p.m., a ruling that could be challenged in court.
Voting by mail was also an issue in Indiana, where the state’s rapid expansion of that process brought confusion and frustration, particularly in Indianapolis. The city had set a deadline of noon Tuesday to return mail-in ballots, yet polls for in-person voting were open until 6 p.m.
Republicans in Indiana’s Fifth Congressional District, which includes the northern swath of Indianapolis and counties to the north, were choosing among 14 candidates to replace Representative Susan Brooks, who is retiring. Democrats believe the seat will be competitive in November.
Some states with primaries on Tuesday saw surges in turnout as tens of thousands of voters cast ballots from home for the first time.
In Johnson County, which includes the University of Iowa, more people voted by mail in Tuesday’s election than had voted absentee in any contest ever, according to John Deeth, a county elections official.
Very few people in Iowa turned out to vote in person Tuesday. By 2 p.m., just 56 people had voted at the Coralville Public Library, according to Zach Wahls, a Democratic state senator who helped organize young people to work at polling sites so the state’s usual crop of older poll workers could be spared the risks of the pandemic. During the 2018 primary, 287 people voted in person at the library.
“We had a voter every 10 minutes or so,” said Mr. Wahls, who killed the time by reading “The Jungle” by Upton Sinclair. “It was very slow.”
In Montana, where both parties have competitive primaries for governor, more than 57 percent of registered voters had returned mail ballots by Tuesday, the highest turnout of any 2020 state primary, according to the Vote at Home Institute, which promotes voting by mail.
All 56 Montana counties chose to conduct the primary entirely by mail after Gov. Steve Bullock, who is himself on the ballot in a lightly contested Democratic primary for the Senate, allowed counties to do so.
The night’s most prominent contest involved Mr. King, who had long been among the most aggressive opponents of illegal immigration in Congress and was once photographed with a Confederate flag on his desk. He was finally disowned by his fellow Republicans after he made his comments about white nationalism in a New York Times interview last year. House Minority Leader Kevin McCarthy stripped Mr. King of his committee assignments, leaving him with little power to influence legislation.
Tuesday’s contest represented the toughest challenge of Mr. King’s career. Randy Feenstra, a state senator who has the support of Iowa’s Republican political establishment, raised three times as much as did Mr. King while touting himself as an effective surrogate for Mr. Trump and conservative values.
Three other Republicans were on the ballot in Iowa’s Fourth District, which covers the northwest quadrant of the state. The crowded field could benefit Mr. King; if no candidate receives at least 35 percent of the vote, the nomination will be decided by local party activists at a district convention, terrain likely to be more hospitable to Mr. King’s grass-roots politics.
The winner of the Republican primary will face J.D. Scholten, a Democrat and former minor-league baseball player who lost the 2018 general election to Mr. King by just 10,000 votes. Democrats believe Mr. Scholten could beat Mr. King but would face far longer odds against Mr. Feenstra.
Iowa Democrats were choosing a candidate to face Ms. Ernst. The Senate Democrats’ campaign arm endorsed Theresa Greenfield, a businesswoman who has proved to be an able fund-raiser and who consolidated support of the state’s Democratic political establishment. Yet Ms. Greenfield has three stout primary opponents, the strongest being Michael Frankel, a retired Navy vice admiral.
Elsewhere, Democrats in northern New Mexico will decide whether to hand the nomination for a safe congressional seat to Ms. Plame, the former C.I.A. agent, or to Teresa Leger Fernandez, a local lawyer who has the support of the Congressional Hispanic Caucus.
And in Montana, Representative Greg Gianforte, a Republican who lost the 2016 governor’s race to Mr. Bullock, is trying once again. Mr. Gianforte made national headlines in 2017 when he pleaded guilty to misdemeanor assault for attacking a reporter. He is locked in a tough primary with Tim Fox, the Montana attorney general.
The winner will face either Mike Cooney, Mr. Bullock’s lieutenant governor, or Whitney Williams, a businesswoman who is backed by Emily’s List, an organization that supports Democratic women seeking office.