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It should be no surprise that Democrats are moving left when the economy hasn't been moving in the right direction for so many people for so long now.

Indeed, according to the World Inequality Database, the wealthiest 10 percent in the United States have seen nearly 50 percent of all the growth since 1980. At the same time, the bottom 50 percent have seen only slightly more than 10 percent of growth. That the typical household now tends to work a little more, be a little smaller and still get help from the government safety net means that living standards haven't completely stagnated for the non-rich. Even then, though, that's left us with what has become a very Dickensian reality: It's a tale of two economies, where it's the best of times for a very few people at the top and, if not the worst of times, at least pretty tough times for everybody else.

All of which is to say that while Alexandria Ocasio-Cortez's shock win over longtime incumbent Rep. Joseph Crowley in Tuesday's New York Democratic primary was certainly dramatic, it was still in keeping with the party's recent ideological evolution. A generation of activists who are too young to remember the defensive crouch into which Ronald Reagan sent Democrats during the 1980s and 1990s, but not too young to have a lot of student loans, are pushing the party to get over its fear of being branded in favor of big government and to adapt to the challenges of the 2000s and 2010s. People, after all, will look to the government to help them when the markets won't.

It wasn't always this way. It might have become a term of abuse the past few years — intra-left fights inevitably involve one side denouncing the other as “neoliberal sellouts” — but the truth is that the Democrats' turn toward markets worked a lot better than it was given credit for.

President Bill Clinton's budget-balancing might have lacked the excitement of a new New Deal, but by allowing the Federal Reserve to keep interest rates low it helped engineer a high-pressure economy that gave workers the best inflation-adjusted raises they'd gotten in a generation. Similarly, President Barack Obama's health-care plan in large part used the private insurance system to try to cover people who were not already covered. This success story was a little less clear-cut for markets since a lot of the people who received insurance through the Affordable Care Act — around 20 million in total — got their coverage through the law's Medicaid expansion. But overall the ACA mostly worked the way the Democrats hoped it would. The uninsured rate fell to an all-time low, and people with preexisting conditions no longer faced discrimination in health-care coverage.

Democrats really were able to achieve liberal ends with conservative means. Just not enough, and not anymore.

The problem is that the forces arrayed against the middle class — offshoring, automation and the ever-rising costs of health care and education — are so strong that it's difficult to make much more than a dent in them if you're trying to use only market forces and not government intervention. Although, as we're finding out, it's not always easy to make a dent at all through the markets. Wages, after all, aren't rising any faster now that unemployment is under 4 percent, and the high-deductible plans that were supposed to keep costs down by making people more conscientious consumers of health care are — surprise! — pricing people out of care. People need more help. They need the government.

Which brings us to Ocasio-Cortez's platform. The broad outlines certainly make sense — a more active role for the government in helping people find work and getting health insurance. But it's not enough just to call for bigger government. It has to be better government, too.

“Medicare for All,” to take one example, is a great slogan that would be terrible politics and policy if it meant forcing everyone into the program. The tricky thing about health care is that as much as people don't like the system, they tend to like their own insurance plans. Telling them that they'd have to give up the coverage they like — by arguing that they'd pay less in new taxes for Medicare than they do in premiums for their current plans — would lead only to a huge backlash. Not to mention all the chaos that would arise from pushing private insurers out of business. It would be far better to give people the option to sign up for Medicare instead. That would let the government cover people directly in what are comparatively low-cost plans without disrupting everyone else's care. That would also push private insurers to keep their own prices down to try to compete with Uncle Sam. That last part, you see, is why budget scorekeepers think something like this would save the government about $150 billion over a decade on the private insurance it's already subsidizing for people.

It would be the same story with a “federal jobs guarantee,” the other big part of Ocasio-Cortez's economic agenda. If that guarantee means that the government would have to hire everyone who wanted a job, it's hard to see how that wouldn't just turn into an expensive make-work program that people would cycle in and out of. That's how some in both the center-left and the socialist-left, in a rare moment of agreement, have criticized the idea. It would make more sense for the government to hire more people, with a particular focus on what we need for the long term — say, universal pre-kindergarten or better infrastructure — and what parts of the country need the most help.

If all of this sounds like the parts of the Obama agenda that, in the case of infrastructure, got blocked by Republicans, and, in the case of a public health-care option, was blocked by centrist Democrats as well, that's because it is. These were good ideas then and still are now. This isn't socialism, despite what critics might have said, but it doesn't need to be to make a difference. We just need a government that's willing to lend more of a helping hand when people need it. And  they do need it.

The era of big government being over is over.