(CNN) In his press conference a day ago, President Donald Trump issued a challenge to newly empowered Capitol Hill Democrats: "Come on," he said, "let me see what you have."

Hours later, Vermont Sen. Bernie Sanders offered a preview of what he hopes the party, led by its incoming House majority, will offer up.

Sanders, who plans to meet with House allies next week, will push for Democrats there to advance the first step of his "Medicare for all" bill's four-year phase-in plan, which would lower the eligibility age for Medicare to 55 from 65 and cover everyone under 18-years-old.

"That is a wildly popular piece of legislation," he told CNN in a phone interview. "Would I be shocked if Donald Trump says, 'You know what, that's a good idea and I'm going to run around this country telling people that I, Donald Trump, not only saved Medicare but I lowered the eligibility age?' Would I be shocked if he came out and said that? No, I would not."

Trump, he said, is a "total opportunist" with "no political ideology" -- the kind of politician whose thirst for adulation might, under certain circumstances, lead to his signing, or even championing, just about anything.

Sanders, who is considering another run at the Democratic nomination in 2020, has often derided the Trump as a fraud who lied to struggling Americans during his campaign. By giving him an opportunity to aid the working class, the thinking seems to go, Democrats could either see their own policy agenda enacted or, in that still unlikely event, force Trump to shoot down what they expect to be broadly popular initiatives.

Democrats tossed around a similar logic shortly after the 2016 election, when infrastructure was looked at as a potential bridge between the parties. But the Republican-controlled House and Senate, with Trump's backing, decided to plow forward with long-promised plans to repeal Obamacare. Trump, like he did on Wednesday, has occasionally talked up bipartisan negotiations on issues like immigration reform, only to eventually pull back and side with Republican hardliners and step up his own anti-immigrant attacks.

The difference now, Sanders reasoned, is that Democrats will, for the first time during Trump's time in office, have the ability to set the agenda -- and a real hand to play in any potential negotiations. He is also planning to push House Democrats to move a bill increasing the federal minimum wage.

"In a few months, what I would hope to see is legislation to raise the minimum wage to $15 an hour and get that legislation to the Senate," Sanders said, issuing a challenge to his Republican colleagues: "And let the Senate vote against that if they want."

Sanders isn't the first to view the President's vanity as a potential avenue for advancing his own agenda. But the stakes here would be different, and more fraught, especially for a likely 2020 presidential primary candidate. His standing with the Democratic base -- if not his supporters on the progressive left -- risks damage for even entertaining the idea of engaging with Trump, whose presidency Sanders himself described as an "existential danger to everything this country stands for."

The complications would grow if Trump takes the bait and, as Sanders put it, uses a potential agreement as a pretense to "run around the country telling everybody what a great president I am." However fanciful it all might seem in the moment, Trump wouldn't be the first president to cut across party lines in pursuit of a political boost following a midterm setback.

Sanders dismissed the suggestion that Trump could turn the tables on Democrats, using a relatively short term spike in popularity to grow his own power and eventually do longer term damage to the same programs, like Medicare, that Sanders wants to protect and expand.

"I think everybody in America will understand the difference between Trump's first two years and this third and fourth year, and everybody will understand that he's responding to what Democrats have done," Sanders said. "If the argument is that suddenly Trump becomes an advocate for a $15 minimum wage is going to make him more popular, more difficult to beat (in 2020), I don't see it that way."

The new balance of power in Washington has lots of people looking at things through a new lens. Even as Trump declared the midterm results a "Big Victory" for Republicans, at a press conference on Wednesday, he mused frequently about negotiating with Democrats, including once and potentially future House speaker Nancy Pelosi.

"We believe that we have a responsibility to seek common ground where we can," Pelosi said at her own news conference. "Where we cannot, we must stand our ground, but we must try."

Sanders, who like so many other rumored 2020 contenders traveled extensively ahead of the midterms with a handful of stops in states that figure to play a decisive role in the primaries, called the Democratic midterm victories "a rejection of not only a reactionary president, who has tried to throw millions of people off health care and give tax breaks to billionaires, but also a rejection of his racism and sexism and homophobia and xenophobia."

He touted the successes of the candidates he stumped for, singling out Pennsylvania's newly-elected lieutenant governor, John Fetterman, Michigan Govenor-elect Gretchen Whitmer, whose primary opponent he endorsed before traveling to Ann Arbor last month in a show of support for the nominee, Wisconsin Sen. Tammy Baldwin and the state's Democratic governor, Tony Evers.

"Evers in Wisconsin was just a wonderful, wonderful victory," Sanders said, "because he ended up defeating one of the most reactionary governors in America, in Scott Walker."

Sanders called the narrow defeat of Tallahassee Mayor Andrew Gillum, a progressive populist he called his favorite candidate of the 2018 cycle, in the Florida gubernatorial race the most disappointing outcome on an otherwise positive night. But even in losing, Sanders argued, Gillum had smoothed the way for Democrats in future campaigns.

"What Gillum managed to do in a very difficult state, not to mention dealing with all the racism that comes against him, is run on a progressive agenda and to mount a really, really very strong grassroots campaign," Sanders said. "Enormous amount of excitement. So while he lost, he took Florida a step forward to become a blue state."