Klobuchar, 58, becomes the fifth US senator and the fourth female member in the chamber announcing a bid for the presidency.
It was a festive atmosphere on a cold and snowy day in Minneapolis as an exuberant crowd for Ms Klobuchar's announcement at Boom Island Park, with the city's skyline in the background, for her campaign kick-off on Sunday afternoon.
Her resumé. Klobuchar is a Minnesota native who graduated from Yale and the University of Chicago Law School.
But some former Klobuchar staffers, all of whom spoke to HuffPost on condition of anonymity, describe Klobuchar as habitually demeaning and prone to bursts of cruelty that make it hard to work in her office for long.
Klobuchar, 58, now in her third six-year term as a senator for Minnesota, will seek to position herself as a contrast to Trump, who is expected to be the Republican candidate in the November 2020 election, focusing on both policy differences but also style and tact. They include Elizabeth Warren of Massachusetts, Kamala Harris of California, Cory Booker of New Jersey and Kirsten Gillibrand of NY.
The Minnesota Democrat appeared on major Sunday morning news shows nine times in 2018, according to data analyzed by Media Matters for America, a nonprofit organization that tracks guests on such shows. Her first appearance on NBC's "Meet the Press" was a televised debate against her GOP opponent during the 2006 U.S. Senate campaign.
A talented orator with a flair for the dramatic, he drew attention for his performance during confirmation hearings of Trump Supreme Court nominee Brett Kavanaugh. Her voting record is that of a traditional Democrat: she's been a past supporter of middle class tax relief, Obamacare and a minimum wage hike. "Bad timing. By the end of her speech she looked like a Snowman (woman)!" the president tweeted.
"I will never let you down", Trump pledges at National Prayer Breakfast
This may have been Trump's big night, but let's not forget the State of the Union was delivered in Nancy's House. "Every life is sacred and every soul is a precious gift from heaven", he said, to raucous applause.
"And I think that she's a smart, articulate, inspiring woman", Pecinovsky said.
"We know that [Klobuchar] is one of the most effective senators in the country", Smith said.
Four unnamed staffers said going public about Klobuchar's character just before her 2020 bid announcement is important. Some progressives said she'd lacked the kind of fire and bold ideas needed to bring significant change and excite voters.
"Our nation must be governed not from chaos but from opportunity", Klobuchar said. She's beloved in her state as a smart, amusing and personable lawmaker and has gained national attention for her lines of questioning at high-profile hearings.
She has been measured in her criticism of Trump, attacking the effects of his trade tariffs on farmers but avoiding more explosive issues like immigration and gun control. The United States had pulled out of the accord in 2017 after Trump assumed Presidency following his win in the 2016 Presidential elections. After living with the orange rage of Trump, Klobuchar's "Minnesota-nice" persona is a welcome relief. She began her career in private practice before being elected narrowly as Hennepin County attorney in 1998. "I have I'd say high expectations for myself, I have high expectations for the people who work for me, but I have high expectations for this country".
Klobuchar responded to questions about the reports Sunday.