The Ryan budget depends entirely on unspecified tax reforms and the replacement of revenues he doesn't care for (such as those associated with Obamacare) with others he doesn't care to actually define or describe. The rigorous, widely respected Center on Budget and Policy Priorities slammed the exercise, taking Ryan to task for failing to live up to his billing as the guy courageous enough to put his ideas out there.
It wrote, "Is it courageous to propose tax cuts but not identify a single tax expenditure to rein in? Is it courageous to target your deepest cuts on the poorest Americans, who vote in lower numbers and provide little in campaign contributions? Is it courageous to camouflage hundreds of billions in cuts for the poor and disadvantaged in broad budget categories without identifying the programmatic cuts, so that analysts, journalists, and other policymakers can't identify the specific cuts and assess their impacts?"