When the results came in from the three tiny towns that traditionally vote first in New Hampshire, Amy Klobuchar posted them straight to Instagram. “We’re off to a great start in New Hampshire today!” the Minnesota senator wrote about the midnight tallies from Dixville Notch, Millsfield and Hart’s Location, which showed her ahead of the Democratic pack with a total of eight votes.

But her joke presaged a successful night that has saved her campaign, at least for now. Klobuchar came in a strong third in New Hampshire with nearly 20% of the vote, behind her fellow moderate Pete Buttigieg on 24.4% and the Vermont socialist Bernie Sanders on 25.7%.

Some of the credit can go to her punchy performance in Friday’s debate, in which she attacked Buttigieg for his youth and inexperience, telling him that “59 – my age – is the new 38 up here”. The jab also drew attention to the fact that the other top contenders – Sanders, Elizabeth Warren and Joe Biden – are all in their 70s.

Klobuchar also criticised Buttigieg for saying he would rather watch cartoons than Donald Trump’s “exhausting” impeachment trial. “It is easy to go after Washington, because that’s a popular thing to do,” said Klobuchar. “It is much harder to lead, and much harder to take those difficult positions.”

While Buttigieg presented himself as a “cool newcomer”, she said, “I don’t think that’s what people want right now. We have a newcomer in the White House and look where it got us. I think having some experience is a good thing.”

Klobuchar was born in Plymouth, Minnesota, in 1960. After studying at Yale and the University of Chicago Law School, she practised as a lawyer and then moved into politics. She joined the Senate in 2006 and gained a reputation for working across the aisle, taking a trip to the Baltic states and Ukraine with the Republicans John McCain and Lindsey Graham in 2016.

She played a memorable role in the heated confirmation hearings for the supreme court justice Brett Kavanaugh in 2018, asking the judge if he had ever been blackout drunk. “I don’t know. Have you?” he asked, repeating the question aggressively. “I have no drinking problem,” she replied calmly. Minutes before, she had talked about her father’s struggles with alcoholism. Kavanaugh later apologised.

Kavanaugh asks Sen Klobuchar multiple times if she's had alcoholic blackouts. pic.twitter.com/3huBRb2JEo — Josh Marshall (@joshtpm) September 27, 2018

Klobuchar has been accused of bullying by former staff members, with one aide allegedly hit by a flying binder. A bizarre story recounted by the New York Times claimed she used a comb to eat a salad in the absence of a fork and then gave it a staff member and told them to clean it. “Am I a tough boss sometimes? Yes,” she has said when asked about the allegations. “Have I pushed people too hard? Yes.”

Her policies as a presidential candidate are probably best described in relation to her more leftwing rivals. She thinks the “green new deal” – a proposed programme to tackle climate change and create jobs – is too ambitious and expensive, and she makes the same argument about Medicare for All, a policy backed by Sanders and Warren that would replace the health insurance industry with a publicly run scheme.

Aware that she needed to seize her moment in the national spotlight, Klobuchar used her speech in New Hampshire on Tuesday night to look past her party and address the nation. “Hello America, my name is Amy Klobuchar and I will beat Donald Trump,” she vowed.

But she faces an uphill struggle to unite the Democratic centrist vote, which is now split between Buttigieg, Biden and her, plus Michael Bloomberg who plans to join the race on 3 March for Super Tuesday. “There is no evidence that she can get non-white voters,” one Democratic source told Politico. She is polling in low single digits in Nevada and South Carolina, the next states to vote, and is doing only marginally better nationally.

As Sanders surges forward on the left and Biden fades, Klobuchar has a small window to make her case.