Senator Bernie Sanders wants to be president—he made that much clear with his energized campaign in 2016. Senator Elizabeth Warren does, too, as several recent moves show. They both have widespread name recognition and share similar political philosophies. Is there room enough in a Democratic primary for the two of them?

That was the premise of a Politico article last week about how the “two progressive behemoths [are] on a collision course in the presidential primary.” Sanders told the outlet that he has not spoken to Warren about their respective ambitions, but added, “I suspect that in the coming weeks and months, there will be discussions.”

Warren and Sanders recognize that they share the same lane in a presidential race: They’re both populists dedicated to fighting economic inequality. Splitting the vote and missing the opportunity to elevate that signature issue in presidential politics would be a worse fate than any extinguished personal ambition.

But Warren and Sanders are hardly identical progressives. They have markedly different approaches to empowering the working class. In the simplest possible terms, Warren wants to organize markets to benefit workers and consumers, while Sanders wants to overhaul those markets, taking the private sector out of it. This divide—and where Warren or Sanders’s putative rivals position themselves on it—will determine the future of the Democratic Party for the next decade or more.

Warren’s suite of policies, rolled out in recent months, all try to reform rules that empower the wealthy at the expense of regular Americans. Her Accountable Capitalism Act would ensure worker representation on corporate boards, and require large corporations to consider all its stakeholders—not just investors but workers, consumers, and communities of interest—in any decision-making. Her climate bill would force public companies to disclose climate-related risks, giving investors more information to use their money toward sustainable goals.

Her housing bill would transfer money for affordable housing to communities that adopt zoning policies to make it easier to build. Her 21st Century Glass-Steagall Act seeks structural separation of commercial and investment banks to keep companies making the riskiest trades away from taxpayer-funded bailouts. And the Anti-Corruption and Public Integrity Act would buttress these gains by reducing the role of special interest lobbying in federal policymaking.

Sanders, while concerned with making markets fairer, would rather just rip them up, either through limiting how much companies can grow or instituting publicly funded options alongside them. He would put a hard cap on the size of financial institutions to make them more manageable. He would make public colleges and universities tuition-free, rather than expanding access for certain needy students. He would create a federal jobs guarantee through 2,500 American Job Centers nationwide, and he estimates that his $1 trillion infrastructure investment would support 13 million publicly funded jobs as well. And in health care, he would simply nationalize the insurance sector, putting everyone on a Medicare-style plan.

I am leaving out some nuance. Both Warren and Sanders support single-payer health care, an example of nationalizing a market. They both want a public option for financial services through simple bank transactions at the post office. Sanders’s Workplace Democracy Act changes the rules to make it easier to form unions, a classic market-restructuring move. His proposed bill to tax employers whose workers receive federal benefits influenced Amazon’s increase of its entry-level wages, and that was the intent: organizing private-sector labor markets without taking them over or imposing standards.

But the two senators disagree over the best method to give the working classes a leg up. You can restructure markets so everyone benefits, or you can break down the market system, either eliminating the profit motive or giving everybody a public option. The impulse is the same: The game is rigged and must be fixed. But there’s a long gap between re-writing the rules of the game, as Warren wants, and turning over all the chess pieces, as Sanders does.

What makes more sense? It’s not necessarily a clear-cut choice. Market-based health care has proven more expensive everywhere it’s been tried, and as practiced in the United States it leads to worse outcomes. Even there, however, market competition can yield success. One of Warren’s biggest legislative victories involved breaking up the hearing aid oligopoly, which required doctor prescriptions for all audiological devices. Since passing a Warren-written law allowing for FDA-approved, over-the-counter hearing aids without medical evaluation, competitors have jumped into the space, driving down the cost of audio assistance for everyone.

Liberals prefer the concept of a mixed economy—which even Sanders supports, more than his democratic socialist branding would imply. Competition can come from the public sector or the private sector: Breaking up the banks through size caps, or separating their investment and deposit-taking wings, gets you to the same place functionally. The public sector may be better positioned to build a road, and the private sector better positioned to sell you sandwiches.

There’s room for this mixture, but only if markets are bent to the will of the people, as in Warren’s conception. As long as the private sector can get away with pursuing profit at the expense of the public, even the deepest interventions into the market might not succeed. Even under single-payer health care, private hospitals and other providers would still be delivering medical care, and they are so concentrated that they would still facilitate waste and frustrate outcomes. Plus, on a practical basis you can certainly restructure markets faster, in many cases without new approval from Congress. For example, antitrust laws still exist, and regulators with sufficient political will can start enforcing them.

Sanders’s policies are appealing to voters in the way that throwing out a system that doesn’t work is inevitably more appealing than tweaking it. But fighting corporate power and making the rules work for people can also resonate on the campaign trail. Warren has been talking about how the game is rigged as long as Sanders has.

That’s why you see competitors to Warren and Sanders alternately picking up market-restructuring and market-overhaul policies. Senator Cory Booker wants to transfer wealth to young people through a social wealth fund, and also block mergers in food and agriculture markets. Senator Kirsten Gillibrand wants a public option with postal banking and a financial transaction tax to nudge markets away from securities trading.

The decision between Warren and Sanders as the standard-bearer on the left is not merely about personality or electability. It will have implications about what Democrats stand for: a party that wants to make capitalism work for everyone, or one that will nationalize parts of capitalism that don’t work. Ultimately, Democratic voters will have to decide which vision they prefer.