Sen. Sherrod Brown, an Ohio Democrat who said he is weighing a presidential bid, speaks with Judy Schmidt of Dubuque, Iowa, during a meet-and-greet at Inspire Cafe on Feb. 2. (Jessica Reilly/AP)

This year’s bumper crop of Democratic presidential contenders all promise to unite the country after years of growing political polarization. But they offer widely differing visions of how to do that, providing primary voters a stark choice over the best route to reclaim control of the White House.

For Sen. Sherrod Brown (D-Ohio), who made his first visit in years to Iowa last week, the message was delivered in two parts. First, he denied any need for Democrats to decide between appealing to his party’s liberal base and Midwestern working-class voters.

“For us, it’s not either-or,” Brown said on the Wednesday launch of his Dignity of Work toura potential precursor to a campaign announcementparaphrasing a line that Barack Obama borrowed from Martin Luther King Jr. “We will always do both.”

Then Brown made clear his special connection to working-class white voters by traveling to a town of fewer than 4,000 residents in a rural county where Obama and President Trump won consecutive elections by more than 20 percentage points.

“I worry about Democrats talking to workers and winning places like Howard County and winning places where Democrats don’t do so well, in small-city Ohio and small-city Iowa,” he said after an event at the Iowa Wrestling Hall of Fame.

For Sen. Cory Booker (D-N.J.), the unity argument was much the same, though he began his appeal from the other side of the geographic and demographic divide.

In his first television appearance since launching his bid Friday, he promised to fight “a caustic type of politics that wants to pit us against each other and create the illusion of separateness.” But instead of showcasing rural America, his announcement video told the story of his family’s struggles against racial bigotry, his deep ties to inner-city Newark and his efforts to champion black students.

The different approaches have less to do with policy than political strategy, as the Democratic candidates remain relatively united on the broad direction of their policy focus — the need for more progressive tax policy, expanded health-care coverage and continued advancements in the fight against discrimination based on race, gender or sexual orientation. (The areas in which some disagree — foreign policy, for example — have not been high on the agenda for voters or candidates so far.)

Instead, the Democratic contenders are offering contrasting story lines for knitting the country back together at a time when racial, ethnic, gender and geographic differences increasingly determine political allegiance.

“Every candidate is choosing a different emphasis, and a lot of the conversation about ‘false choices’ comes when we are being asked to say a difference in emphasis is about a difference in visions,” said Pete Buttigieg, the mayor of South Bend, Ind., and an announced presidential candidate.

A military veteran in a same-sex marriage, Buttigieg is running for president with a campaign that emphasizes his youth and the Midwestern focus on the “everyday problems” of voters. The trick, he said, was finding a message that appeals broadly instead of different sales pitches for different groups. “Meaningful coalition building is when you find the things that lots of people care about,” he said.

Sen. Kamala D. Harris (D-Calif.) speaks during a rally launching her presidential campaign in Oakland, Calif., on Jan. 27. (Noah Berger/AFP/Getty Images)

Democratic strategists have long debated the best route for creating an electoral majority to take back the White House in 2020, with visions that vary in their focus on increasing turnout by nonwhite voters, winning educated suburban voters and regaining support among working-class whites. While Democrats have increased their margins among college-educated and female voters in recent cycles, the Republican share of white voters without college degrees has also been growing.

Trump has capitalized on these divisions by embracing demagogic rhetoric that tends to drive enthusiasm among a large share of the working-class white vote. He has launched crusades against Muslim and Hispanic immigration, described countries in Africa and the Caribbean with a crude epithet and elevated cultural controversies, such as black football players’ kneeling to protest police misconduct.

In response, Democrats have identified reunifying the country as a central theme for any winning Democratic nominee. The strategy has been embraced by centrists as well as more liberal leaders.

“I think unity is the ultimate payday in the primary,” said former Colorado governor John Hickenlooper, who is preparing a campaign that will be based on his success bridging geographic and partisan divides in his state. “There are divisions right now between almost every group in this country. I view the priority in each case as how we can bring these groups together.”

Sen. Kamala D. Harris (D-Calif.) has also become a leading voice in arguing that Democrats do not need to make a choice between appealing to non-college-educated whites and the party’s multicultural base. At the same time, she has embraced the potentially historic nature of her campaign, launching her effort on Martin Luther King Jr. Day with a campaign logo inspired by Shirley Chisholm, the first black woman to be elected to Congress and to run as a major-party presidential candidate.

When asked on the day of her campaign announcement whether she identifies more with the Jamaican or Indian heritage of her parents, Harris said, “I describe myself as a proud American.” She then said that such identity politics would not define the coming election.

“We are a diverse country, yes. Some people would suggest that in diversity, when there is a diverse population, one cannot achieve unity. I reject that notion,” she said in a news conference at Howard University, her alma mater. “This is my belief: Yes, we are diverse, and we have so much more in common than what separates us.”

Like Booker, she has gone further than Obama in 2008 to make her racial identity a centerpiece of her campaign, a fact that has been noticed by some of his former strategists. Obama, who won office by saying that he would transcend political divisions in the country, became more outspoken on issues of racial justice after winning reelection.

“He always used to say,I am of the African American community, but I am not limited to it.’ He never ran on that,” said David Axelrod, the chief strategist for both of Obama’s presidential campaigns. “She is making symbolically a much more overt appeal around her identity.”

Sen. Kirsten Gillibrand (D-N.Y.) has made gender identity a centerpiece of her campaign in an effort to win the growing share of female voters who support Democrats. “Our future is: female, intersectional, powered by our belief in one another,” Gillibrand tweeted last year, referencing a theory focusing on how forms of discrimination intersect.

Former Obama administration housing secretary Julián Castro, who has described his campaign as a continuation of a long national fight against discrimination, has shaped his campaign platform agenda around the idea that his policies on health care, education and government transformation will help everybody.

“We have had the most divisive president in our lifetime with Donald Trump,” Castro said. “I see myself as the antidote to that.”

As Brown traveled through Iowa, the cultural divisions in the country were top of mind for some Democratic attendees at his events. They said they were looking for a candidate like Brown who knew how to reach rural areas.

“Having many friends in both parties, he is one that can appeal to my friends,” said Mark Rhodes, a history teacher in Decorah, Iowa, who attended Brown’s first stop in the state. “It has unfortunately gotten very tribal over here.”

Brown and his wife, journalist Connie Schultz, also made sure to lay down markers of their cultural connections to the region. In her introductory talks before events, Schultz told the story about the “Jack and Jesus wall” at her childhood home, celebrating John F. Kennedy and the Christian messiah.

She also told a story about introducing Brown, a Yale graduate, to her union workman father, who never attended college. “He’s us in a tie,” she says her father told her about Brown, after they shared a meal together.

For his part, Brown, who has not made a final decision on running for president, left little doubt that if he ran, he planned to lean on the cultural and geographic affinities between his home state of Ohio and Iowa.

“We’re both, you know, four letters, three vowels, lots of corn, kind of square,” he said at a house party Friday in Waterloo.

Chelsea Janes contributed to this report.