Democratic lore has been building in Minnesota around Amy Klobuchar for the nearly two decades she's been in statewide politics.

Since she was first elected to the U.S. Senate in 2006, Klobuchar has achieved unquestionable popularity in Minnesota, easily defeating Republican challengers in her two re-election campaigns with more than 60% of the vote.

That popularity is something some Democrats have come to count on — they argue it translates into a down-ballot boost for DFL candidates running for Congress and the state Legislature. Klobuchar, who got her party's endorsement at the DFL's state convention this weekend, is back on the ballot this fall seeking a fourth term in the U.S. Senate.

"She not only wins significantly in parts of the state that other Democrats running statewide underperform in, she has coattails that lift up other candidates running," said DFL Party Chair Ken Martin, who calls Klobuchar the "speaker-maker" for helping to flip the state House. "She's not only one of the most popular politicians, she has amazing staying power."

Using voter data going back more than three decades, an analysis found a correlation between election years when Klobuchar is on the ballot and better results for Democrats in many other races. She's consistently won her elections with a larger percentage of the vote than other statewide candidates, and every year she's run, the DFL Party has won whichever chambers of the Legislature were on the ballot.

The DFL flipped the state House and held the state Senate in 2006, the year the then-Hennepin County attorney first ran for U.S. Senate. The state House and Senate both flipped to DFL control in 2012, Klobuchar's first run for re-election. The Senate was not on the ballot during her third race in 2018, but the House flipped to DFL control after being held by Republicans for four years.

Years when Klobuchar runs statewide typically see a higher overall performance for DFL candidates in the U.S. House, state House and state Senate compared to other years. Democrats are trying to hold control of the Minnesota House and the flip the U.S. House this fall.

Jeff Blodgett, a DFL operative who has worked on statewide U.S. Senate and presidential campaigns in Minnesota, said Klobuchar's own personal brand of politics enhances the party's broader brand, especially with independent voters. Her focus on middle-class economic issues such as price gouging, junk fees and monopolies has helped endear her to a broad set of voters, he said.

"Independent voters in Minnesota find her familiar, comfortable, likable," he said. "Increasingly, it's a nice contrast to the harsh, extreme candidates the other side puts forward."

But longtime Republican consultant and campaign operative Gregg Peppin said Democrats' overall success in years Klobuchar has been on the ballot is "largely coincidental."

The 2006 election was good for Democrats across the board amid backlash to the George W. Bush administration and the war in Iraq, he noted. In 2012, Barack Obama sought a second term and Minnesota Democrats turned out to oppose constitutional amendments to ban same-sex marriage and require an ID to vote. Democrats across the country did well in 2018, the midterm election during Donald Trump's presidency.

"Elections are much more determined by external events and the external environment than they are by one person on the ballot," Peppin said.

The 2024 election year will be different, with a race largely driven by how people feel about the rematch between former President Donald Trump and President Joe Biden, he said. Klobuchar's fourth run for the Senate will also be her first since her 2020 presidential campaign.

"Biden isn't that popular, and she hasn't been in that situation where there has been an unpopular Democrat at the top of the ticket," Peppin said. "She also ran for president herself and some Minnesotans might have questions."

Republicans have endorsed former NBA player and Steven Bannon acolyte Royce White to run against Klobuchar this fall, but he could face a GOP primary challenge from former naval officer and businessman Joe Fraser.

The bigger battle for the DFL may be internal, said Annette Meeks, a longtime Republican operative. Democrats in the Twin Cities have moved further to the left and pushed issues that Klobuchar has not, she added.

"The DFL has to decide who they are: Are they the moderates, like Amy Klobuchar and her ilk, versus the more radical wing?" Meeks said. "She might have to answer some tough questions about that in certain parts of the state."

Klobuchar was last on the ballot during a presidential year in 2012. She outperformed Obama by more than 300,000 votes, in part because she travels to every corner of Minnesota, said Mike Erlandson, a former DFL Party chair.

"Some people say it's silly that she visits all 87 counties every year, but it's things like that that keeps her connected to Minnesota voters in a way other [candidates] have not attained," he said.

She also runs like she's 20 points behind, despite not drawing a top-tier candidate in her last two re-election battles, Erlandson said. "That will help Democrats up and down the ballot, from Biden to the U.S. House to the Legislature."

Martin said Klobuchar works with other candidates, and other candidates "want to hitch their wagon to her because she's so popular."

"There are lots of question marks for Democrats right now, but the one constant is Amy Klobuchar."