from the CBO:
*expected to increase as more people sign up
Employer-sponsored insurance deduction =
about $250 billionSo that adds up to about $1.2 Trillion in current federal health spending.
Private health insurance premiums, I've seen estimates very roughly about $1 Trillion. If you take the $250 billion in employer deductions, and $40 billion in exchange subsidies out of that, then you have about $710 in the private market that Medicare-for-all would have to make up. But then figure that Medicaid recipients receive less in reimbursements to physicians than for Medicare, so there will be an increase if these people are moved to Medicaid, and that Medicare can cover more co-pay than many private insurance.
On the other hand, private insurance needs to make a profit, whereas Medicare would not, so that might bring down.
So, I'd guess a need for anywhere from $650-850 billion or so more in annual federal health spending, in order to do Medicare for All, which will increase each year, unless we figure out some major ways to cut health spending inflation. And that is not counting the fact that Medicare is already going to be a major cause of deficits in the future without some either cuts in spending and/or tax increases, as it is, with just the elderly population. This would be tough.
I suppose taking military spending down to zero might be enough in the short term not to increase the deficit, but that is not a serious proposal.
We could take some out of defense, but before we cut the defense budget in any substantial fashion, we need to fundamentally rethink our role in the world as it has been for most of the past century, or else we will be trying to do the same things we have been doing, only without the resources to do it.