Implementing the entire Bernie Sanders policy agenda would cost a staggering $18 trillion, according to a somewhat alarmist Wall Street Journal article about Iowa's favorite social democrat. And it's true. Sanders would substantially increase the size of explicit federal spending.

But his proposals are also more affordable than you might think.

As you can see from the WSJ's handy graphic, this "$18 trillion" cost over 10 years can be basically broken down into two buckets.

There's a $15 trillion Medicare-for-all plan, and then there's everything else. Everything else tallies up to $3 trillion over 10 years. That is a lot of money. It is, however, $400 billion cheaper than Jeb Bush's tax cut plan. So the typical middle-class family will get $942 from Jeb Bush, while in Sanders-land the typical middle-class family will get free college, paid parental leave, and a bunch of new transportation infrastructure — plus Sanders averts the need to cut Social Security benefits or raise the retirement age.

So what about this $15 trillion business? Well, Sanders is proposing to have the federal government pay for everyone's doctor visits, hospital stays, and medical procedures, just the way it currently does for people over the age of 65. Obviously that's an expensive undertaking. But right now private health insurance plans are projected to spend $14 trillion over the next 10 years, and people are forecast to incur $4 trillion in out-of-pocket expenses. Turning $18 trillion of private spending into $15 trillion of government spending while also expanding access to insurance would actually be an incredibly impressive trick. If you financed it with a broad-based payroll tax (the way Social Security is financed), people with job-based insurance plans wouldn't even notice the difference — today's insurance premium line on your pay stub would become a tax line.

The reasonable question to ask about this is not whether it would be affordable, but whether it's actually true that America could pull off this kind of vast expansion of Medicare while retaining its low cost structure. It's certainly possible in theory, but when Sanders's home state of Vermont tried it, the plan collapsed in the legislature over working out the details.