DES MOINES, Iowa - Like others who spoke at a Democratic Party fundraiser here, Sen. Amy Klobuchar, D-Minn., said that so much has changed nationwide since President Donald Trump took office.

"Back in January, on that inaugural stage, I was officially displaced as the most famous Slovenian American by Melania Trump," she joked. "That was hard on me."

"Every time I look at her," Klobuchar deadpanned, "it's like looking in the mirror."

The crowd burst into laughter, but then Klobuchar - known as one of the funnier members of Congress - turned serious, strongly criticizing Trump for his late-night tweets, and his attacks on immigrants, Muslim refugees, federal judges and the news media.

"Donald Trump kind of likes it when we talk about him, right? But here in Iowa, you pride yourself on being first. First in corn production, first in hogs - first in caucuses," she said. "Let's be the first Democratic Party dinner where the rest of the night we don't even mention his name."

That line earned strong applause from about 250 Democrats and independents who showed up Sunday night to hear a little-known senator from a neighboring state who may one day compete in their presidential caucuses. The party's base, intently focused on winning back statehouses and seats in Congress in 2018, is already being courted and prodded by potential 2020 candidates.

"It's never too early, unfortunately," said Tom Vilsack, a Democratic former Iowa governor and agriculture secretary. He advised that a smart presidential candidate will spend less time in Des Moines and more time in smaller, rural areas getting to know the state's legislative and gubernatorial candidates.

That's what Klobuchar did, traveling Sunday to a Democratic fundraiser in Lynn County before heading to Iowa's biggest city, where local Democrats raised $20,000, a big uptick from last year's dinner, which was a potluck. In Des Moines, she name-checked a former congressman, mentioned stops at a Waterloo popcorn shop and an ethanol plant in Mason City - and reminded the crowd that she has visited their state several times.

Before the speech, Klobuchar said that Democrats have done a good job this year "sussing out what kinds of things [Trump] is really going to do. But I think it's time now to start moving forward with an economic agenda and start putting it out there for people."

That agenda is being shaped by the bustling "resistance" and an increasingly active left. For much of Barack Obama's presidency, Democratic activists expected Hillary Clinton to run as his successor. They worked, with some success, to move her to the left on issues including health care, wages and criminal justice reform; they found more success when Sen. Bernie Sanders of Vermont waged a stronger primary challenge than anyone had expected.

Sanders, who will turn 79 in 2020, has deflected questions about a second run. But his influence on the party, and candidates' view of where the party has moved, is unmistakable. In the Senate, his "College for All Act" has been co-sponsored by Sens. Kirsten Gillibrand, D-N.Y., Elizabeth Warren, D-Mass., and Kamala D. Harris, D-Calif. - all considered potential candidates.

His bill to raise the minimum wage to $15 by 2024 has been co-sponsored by that trio, plus Sens. Cory Booker , D-N.J., Sherrod Brown, D-Ohio, and Al Franken, D-Minn. - also mentioned as possible presidential contenders. His bill to expand Social Security has one co-sponsor: Gillibrand. And outside the Senate, Gov. Andrew M. Cuomo, D-N,Y,, viewed with contempt by the left as he plots a 2020 campaign, brought Sanders to New York to help announce a college tuition plan.

Klobuchar mentioned Sunday night that she co-sponsored legislation with Sanders to import cheaper prescription drugs from Canada and that she backed Obama's ideas to shore up community colleges. She touted plans to bolster apprenticeship programs, jobs programs for military veterans and to lessen the burden of student loans on young people.

"If billionaires can refinance their second homes and private planes, I think our students should be able to do the same," she said.

That's the kind of rhetoric that excites groups such as the Congressional Progressive Caucus, which represents a larger-than-ever slice of the House Democrats. The group rolled out its own budget with the expectation that future candidates would crib from it.

"Job creation, child care, our version of tax reform," said Rep. Raul Grijalva, D-Ariz., the co-chairman of the caucus. "Those would be our rallying points both in terms of candidates and in pressuring the major candidates to adopt them. If we do well in 2018, we have a lot of momentum to insist that these are the issues to run on."

For years, Klobuchar and her team have made no secret that she sees herself as a future presidential contender. With an approval rating of 72 percent in a poll published by the Minneapolis Star Tribune over the weekend, she - like Gillibrand and Warren - appears to be coasting toward reelection next year.

The last time she came to Iowa was as a Hillary Clinton campaign surrogate last fall. She likes to remind reporters that she has campaigned for fellow Democrats in more than 30 states during her 12 years in the Senate. Now, she's willing to share gentle criticism of what she thinks went wrong - starting with the former secretary of state's campaign slogan.

"The phrase 'Stronger Together' - as much as it was positive, optimistic words - for a lot of the people in my state - iron ore miners who are out of work - it didn't feel to them like they were into that. It felt like it was a response to Donald Trump," she said in an interview before her visit.

Klobuchar, 56, didn't provide an alternative to "Stronger Together" - "I always liked 'Putting people first,' but that's outdated" - but suggested that it's time for Democrats to move on.

Her argument is at the crux of the identity crisis now roiling the Democratic Party. Should it try to reclaim its previous foothold or at least attempt to close the gap in the Midwest and the South, where Republicans dominate? Or should it focus on bigger blue states and suburban congressional districts that are home to millennials, single women and minorities, who demographers say will play a greater role in future elections?

Klobuchar made clear that she expects the party's future to cut through the Midwest.

"We are the people in the middle of the country," she said in her speech. "There are many of this room who are in the middle class, middle income, even a few who could be described as middle aged. And yes, from time to time, in the middle politically."

In future elections, the region "will not be forgotten," she added. "We have a voice and people should listen."

What role Midwestern states such as Iowa might play in future Democratic contests is an open question. The Democratic National Committee's "unity commission" - created to mollify supporters of Sanders at the end of the Democratic presidential primary - has begun an eight-month process of reforming the presidential selection rules ahead of 2020. In 2016, when Democrats expected Clinton to be elected - delaying the next primaries until 2024 - they preliminarily agreed to weaken the power of independent "superdelegates," to prevent another early rush to one candidate.

At the first meeting over the weekend, Sanders-appointed committee members also argued for the party to disincentivize early primaries and ensure there were early contests where grass-roots support could overwhelm money.

"We are likely to have a much broader field that is more likely to include someone less funded, less well known, but may in fact be the stronger candidate in a general election, have the opportunity to get known," Jeff Weaver, who managed Sanders's campaign, said during the commission's Friday session.

Sean Bagniewski, chairman of the Polk County Democratic Party, is among those who will fight to defend Iowa's early status. He first met Klobuchar in January 2016, when she and Booker stopped by his house for an event held by the Clinton campaign.

"We had 150 people over - and I have a very small house," Bagniewski recalled - but both senators shook hands and posed for pictures with everyone who asked.

Bagniewski, recently elected to lead a county Democratic Party that plays an outsize role in presidential elections, said that after meeting Klobuchar last year, he invited her to come speak and her team quickly accepted. (Booker has yet to respond to a similar invitation.)

"She's about as new of a leader as we get on Capitol Hill from the Democratic Party - new to the national stage," Bagniewski said. Plus, "she's got a Midwestern last name like mine."

Klobuchar - like every other potential 2020 candidate - avoids answering questions about a presidential campaign or at least feigns little interest in loftier political ambitions.

"The United States Senate is the place to be," she told the crowd in Des Moines - echoing what she'd already told The Post. "This is the place where we are going to not only be a place of compromise but also an emergency brake."

She spoke for 38 minutes, and some people sneaked out as she shared detailed thoughts on the party's potential economic message. Many more left quickly when she concluded.

Jess McCord, 35, from Urbandale, Iowa, is a member of a local chapter of Indivisible - a liberal group that has been organizing progressives nationwide.

"That is absolutely more of what I want to see," he said of the senator. "Talk about jobs, talk about putting people back on track. Basically, a progressive economic policy."

McCord is mostly concerned about winning back state legislative seats in 2018. In 2020, "we'll see what else is offered up here," he said. "I think it's going to be a crowded field."