Amy Klobuchar’s expected bid for president will test a formidable home-state brand at the highest level of American politics, as the U.S. senator from Minnesota employs an instinct for issues of broad appeal and a down-to-earth style to woo Democratic voters all over the country.

On Sunday afternoon at 1 p.m., Klobuchar is throwing an outdoor rally along the Mississippi River, just north of downtown Minneapolis. While she won’t say anything definite until the Boom Island Park event, her entry into the race for the Democratic presidential nomination is all but certain.

By Saturday, workers had already assembled large tents and risers at the park site, which features the skyline as backdrop. With the announcement, Klobuchar will join a growing roster of Democratic rivals vying to challenge President Donald Trump in 2020. The group already includes four of her fellow U.S. senators and could grow to include a former vice president and other big names in the party.

Klobuchar will use her speech at 1:30 p.m. Sunday to emphasize her broad appeal, with three convincing statewide wins as evidence. She’s carried rural and Republican-leaning areas, her argument will go, with a pragmatic and hardworking approach that has shown results in Congress by focusing on achievable goals. An adviser shared those details under the agreement that it did not constitute confirmation of her plans.

In her speech on election night last November, after she was reelected by more than 600,000 votes, Klobuchar offered a preview of a possible presidential message.

“We have to stand up not just for those who voted for us but for those who didn’t, and for those who stayed at home and were tired of the divisiveness in our politics,” Klobuchar said. “Because whether you are a Democrat or a Republican or an independent, we are all Minnesotans and we are all Americans.”

As Klobuchar’s announcement approached, Republicans started sharpening their critiques. The Republican National Committee put out a news release Friday flagging several instances in 2018 where Klobuchar pledged to serve her full six-year term if reelected. The RNC piece maintained that despite her “carefully crafted image as a moderate Midwestern senator, Amy Klobuchar has shown that she is just another out-of-touch Democrat.”

Klobuchar, 58, has never lost an election. Leaders of the Minnesota Republican Party, which has had no success in blunting her home-state momentum, frequently criticize her as an overly cautious politician who plays it safe by focusing on broadly popular issues such as consumer protection even as she reliably votes with Democrats on more controversial measures.

“Minnesota Nice is not going to work on a national stage,” said Jennifer Carnahan, chairwoman of the Minnesota Republican Party. “We’ve seen that in the past. People need to get out there and demonstrate true leadership potential.”

For Democrats, there is logic behind a play for the Midwest. Trump won Michigan and Wisconsin in 2016, two states that previously backed Democrats for several decades, and he nearly carried Minnesota.

In 2018, Klobuchar carried 43 Minnesota counties that Trump had won two years earlier. She won 51 of 87 counties overall last year; her high point came in her first re-election bid in 2012, when she carried all but two counties.

Klobuchar also offers a record of legislative success. During the 2015-16 session of Congress, she ranked first among all 100 senators for the number of bills signed into law. In contrast with some of her Democratic rivals, Klobuchar frequently touts collaborations with Republicans.

Still, daunting challenges await. Klobuchar is a lesser-known entrant in a field that could grow to include former Vice President Joe Biden and already features three other women who are also Democratic senators: Elizabeth Warren of Massachusetts, Kirsten Gillibrand of New York and Kamala Harris of California. All three hail from large coastal states with more big-money Democratic donors and larger constituencies of nonwhite voters, an increasingly important bloc for Democrats.

“The problem for her will be like it is for anybody — short of jumping out into traffic, how do you get noticed?” said John Lapp, a D.C.-based Democratic media strategist with experience on national and statewide campaigns around the country.

Lapp suggested Klobuchar “take on something bold” in the fashion of Vermont Sen. Bernie Sanders, who built his 2016 presidential bid on issues such as Medicare for all and free college tuition. Sanders, too, may run again in 2020.

Klobuchar’s first and closest election was in 1998, when she was narrowly elected Hennepin County’s chief prosecutor. Her statewide opening came in 2006, when she defeated a sitting Republican congressman for an open Senate seat.

“Her style, I think, may set her apart,” said Jeff Blodgett, a longtime Democratic strategist in Minnesota who advises Klobuchar. “I would put her in the ‘happy warrior’ category, as someone who tries to be positive and optimistic. In many ways she’s really kind of the anti-Trump.”

As a senator, Klobuchar has pushed for cheaper prescription drugs and to pull unsafe products off store shelves, pursued legislative solutions to human trafficking, opposed corporate consolidation and introduced legislation meant to protect against Russian interference in U.S. elections. She’s a vocal critic of Facebook on issues of both data privacy and political advertising transparency. Her charged back-and-forth with Brett Kavanaugh during his Supreme Court confirmation hearings last September, over allegations of sexual assault against him, became a national breakout moment.

Klobuchar has churned through staff at a fast clip. Last March, LegiStorm — a D.C.-based website that tracks congressional employment — found Klobuchar’s office had the highest turnover of any U.S. Senate office between 2001 and 2016, at 36 percent annually. Among Minnesota Democratic operatives, Klobuchar has a reputation as a highly demanding, at times difficult boss, though she has maintained a handful of long-serving aides, and many former staffers have gone on to other big jobs in Democratic politics.

No Minnesota politician has ever been elected president. Blodgett’s “happy warrior” label alludes to the nickname given to the late Vice President Hubert Humphrey, the Minnesota Democrat who lost the 1968 presidential election to Richard Nixon. Another Minnesotan, former Vice President Walter Mondale, lost the 1984 general election to Ronald Reagan. As a Yale undergraduate, Klobuchar once had an internship in Mondale’s vice presidential offices.

In 2012, former Gov. Tim Pawlenty and former U.S. Rep. Michele Bachmann both ran unsuccessfully for the Republican nomination.

“As Tim Pawlenty and [former Wisconsin governor] Scott Walker showed, it’s really hard to raise your profile as a Midwestern leader in a presidential campaign,” said Alex Conant, a D.C.-based Republican strategist and Minnesota native who worked for Pawlenty’s 2012 bid and Florida Sen. Marco Rubio’s 2016 presidential campaign. “Those campaigns are so intense that if you’re not well-known at the outset or you don’t have a big base of support, it’s hard to get off the ground.”

Staff writer Torey Van Oot contributed to this report.