Democratic presidential candidates Bernie Sanders and Hillary Clinton respond to audience members at the Miami Dade College Kendall Campus in Miami on Wednesday. (Craig Rubadoux/Florida Today via AP)

Simplicity is one of Bernie Sanders's great strengths: Corporations and the rich have rigged the economy. His solutions sound simple, even when the plans behind them are complicated: college for all, health care for all, tax the rich, break up big banks. He trails Hillary Clinton in presidential delegates to this point and remains an underdog for the Democratic nomination, but Sanders has already pulled Clinton, and the party, toward a more populist, more socialist policy agenda, thanks in part to that clarity of message.

The centrist Democrats who oppose that leftward lurch have struggled to match his simplicity. They tend to view the economy through a lens of skills and adaptation, not power and treachery. Many of them pushed in the 1990s, under President Bill Clinton, to expand global trade and deregulate the financial sector. They now concede those efforts did not go according to script, particularly for middle-class workers, but they are not calling for a full rewrite in response.

Bernie Sanders won Michigan on March 8 by getting votes from several key groups. (Peter Stevenson/The Washington Post)

Their risk, in this election and moving forward, is to define themselves solely as anti-Democratic-socialist — the folks who don't like the stuff that a lot of Democrats like about Sanders.

The Progressive Policy Institute is the latest centrist Democratic institution to try to counter that image. Today it will release what its president, Will Marshall, calls a "radical" agenda to get America working for the working class again. The report is called "Unleashing Innovation and Growth: A Progressive Alternative to Populism," and it is organized around a straightforward, if not perfectly simple, principle.

“Innovation is not the problem; it’s how we solve the problem," Marshall says, previewing a 20,000-word agenda that aims to energize America's investment, entrepreneurship and education. "Right now, you’ve got Bernie basically making an argument against the economic changes that have swept away the industrial landscape that he loves so much. Somebody’s got to stand up for the new economy.”

That new economy, in PPI's imagining, draws heavily on public investments — read: government spending — to help the United States lead the world in new ideas, new products and new jobs.

It includes scaled-back versions of what now must be seen as the mainstream progressive agenda, such as a modest minimum wage increase, expanded family leave policies and higher taxes on the rich. It spends more on infrastructure and targeted assistance to industries such as advanced manufacturing and clean energy. It taxes the greenhouse gas emissions that scientists say are driving climate change.

It would create "universal pensions" that would follow employees from job to job if they move and would set up new tax-preferred savings vehicles to help workers buy homes.

Many of the most radical ideas are ones that might make progressives chafe. It proposes to lower college costs not by making tuition free but by encouraging schools to offer degrees that can be completed in three years instead of four, and its plans to "reinvent" public schools include an openness to charter schools and similar efforts to shake up the traditional school model.

PPI advocates a shift from income taxes to consumption taxes, which many economists say would boost economic growth by removing disincentives to work — but which remains a tough sell with voters. It would reduce the corporate tax rate while eliminating some business deductions.

It also pushes more trade expansion (by approving the proposed Trans-Pacific Partnership) and more deregulation (via an independent commission to "prune" current regulations that inhibit innovation, modeled on the process that closes down military bases).

The ideas sometimes overlap with the ones laid out by the think tank Third Way in another anti-populist report last fall. Just as Third Way did, PPI's agenda leads with a blistering critique of Sanders-style socialism. "Today’s populists," PPI proclaims early in its report, "peddle nostalgia for our country’s past industrial glory but offer few practical ideas for building a new American prosperity."

As was the case with Third Way, but even more so now that the campaign is hurtling toward November, the agenda appears to be targeted at Clinton, in the hopes she'll win the nomination and need a revamped platform for the general election.

“If I were Hillary, I would say, look, the status quo is killing us. But we need to change it in ways that get us out of this slow-growth slump," Marshall said.

He sounded hopeful that she would. “She’s always at pains not to be as harsh as Bernie is about corporations, about capitalism in general," he said. "She knows that just saying you’re going to 'stand up' to the drug companies or the oil companies is not going to make prosperity magically appear.”

Senator Bernie Sanders (I-Vt.) made waves as a democratic socialist presidential candidate. Here's what you need to know about being a democratic socialist and how it's different from socialism. (Alice Li/The Washington Post)