Warning of a “weakening Democratic brand,” pollsters working for a progressive nonprofit are encouraging the minority party to run on a clear, populist platform in 2018 — or risk an election where voters don’t see them as alternatives to the Trump administration.

“Trump is hated, but he is not collapsing and is stable on many parts of his identity and job performance,” pollsters Stan Greenberg and Nancy Zdunkewicz wrote in a polling memo prepared for Women’s Voices Women Vote Action Fund, a nonprofit organization. “Democrats must make the main choice in this election about how the Republicans in Congress have gone back on their promises on health care and protecting Medicare, Medicaid and Social Security.”

The poll results, which were provided to The Washington Post on Wednesday night, revisit a pool of voters from the “rising American electorate” — young, diverse and less prone to voting — that was first studied in June. Since the summer, despite President Trump’s struggles, those voters told the pollsters that they’d become a bit less inclined to vote for Democrats in 2018. A 31-point Democratic margin shrank to a 21-point margin.

The problem, according to Greenberg and Zdunkewicz, was a president who blotted out the sun. “It shows a weakening of the Democratic brand, as events and Trump following Bannon’s advice leaves Democrats invisible on the economy and jobs,” they write. “Because voters do not hear Democrats expressing dissatisfaction with the status quo on economics or the balance of power when so many are concerned about the direction of this country, only 4-in-10 … voters say Democrats ‘know what it’s like to live a day in my shoes’ and are ‘for the right kind of change.'”

According to the pollsters, the solution is staring Democrats in their faces. The voters who trust neither party need to be convinced that one party, the Trump-led Republicans, had already betrayed them. One of the best-testing messages mirrored what Democrats had said for years: “Trickle-down has failed and the richest need to pay their fair share of taxes.” They had just not said so effectively about Trump and Republicans in Congress.

“It is time to recognize that these voters will not be motivated unless they hear a message from the Democrat who says he or she is ‘fed up’ and ‘the economy and politics are rigged against the hard-working middle class,’” the pollsters advise. “The message deplores that ‘corporate lobbyists and billionaires spend unlimited money to get their way,’ which is more ‘trickle down’ while ‘people who play by the rules are crushed by the cost of health care, child care, housing and student debt.’ While it ends by proposing a range of changes ‘so American grows the middle class again,’ it is otherwise mostly negative and dramatic.”