"It certainly blows a major hole in his plan," said Paul Van de Water, a health care and budget expert at the Center on Budget and Policy Priorities, in a phone interview.
If you take Ryan at his word, and assume that the tax-side of his plan is revenue neutral -- a big "if" -- his plan balances the budget over decades entirely on the spending side of the government's ledger. Van de Water explains that if you take the Medicare privatization plan out of the equation, the budget sinks -- dragged down by higher spending, and then higher interest payments as a result of larger-than-projected deficits.
"That plus interest gets you into a range where you no longer balance the budget," Van de Water said.
That's not to say Ryan's plan would blow up the deficit. "Would it turn [it] into a disaster? Probably not because he was cutting so much elsewhere in his proposal. He has very deep cuts in in Medicaid, he also has very, very deep reductions in the rest of the government as well."
Of course, eliminating deficits is supposedly Congress' entire raison d'Ãªtre at this point. But if phasing out Medicare is off the table, and tax increases are off the table, that's just not going to happen.