Both campaigns seem to agree that Mitt Romney's pick of Paul Ryan for the veep spot sets up a big, clear policy choice for the election. President Obama's vision for the federal budget is very different from Paul Ryan's. But what do these differences mean in concrete terms? Here's an analysis we did back in March, when Ryan released his 2013 budget, that tried to flesh the differences.

To cut or not to cut? (Elaine Thompson/AP)

Ryan’s budget, recall, would raise $2 trillion less in tax revenue over the next decade than President Obama's budget. Ryan's plan would also spend $5.3 trillion less over that time. A big chunk of this is health care: Ryan would cut federal spending on Medicare and Medicaid for a portion of his savings. But he’d also spend $2.2 trillion less on everything else. So what, specifically, is Ryan planning to cut? (Or, alternatively, what is Obama planning to spend more on?)

The clearest way to figure this out is to look at the “Chairman’s mark.” This is the version of Ryan’s budget that’s in legislative language and gives specific forecasts for spending by government function. You can see them in table form at the end of his bill (pdf) and then compare them with the White House’s Table 32-1 here. Exciting, yes.

Over the next decade, Ryan plans to spend about 16 percent less than the White House on “income security” programs for the poor — that’s everything from food stamps to housing assistance to the earned-income tax credit. (Ryan’s budget would authorize $4.8 trillion between 2013 and 2022; the White House’s would spend $5.7 trillion.) Compared with Obama, Ryan would spend 25 percent less on transportation. He’d spend 6 percent less on “General science, space, and basic technology.” And, compared with the White House’s proposal, he’d shell out 33 percent less for “Education, training, employment, and social services.”

How might this lower spending play out in the real world? Let’s take transportation as an example. Right now, the United States is facing a number of pressing infrastructure challenges. The National Highway System, first built in the 1950s, is reaching the end of its natural lifespan. Our air-traffic control system is outdated, causing airport delays around the country. About one-quarter of the country’s bridges are either “structurally deficient” or inadequate to today’s traffic needs, according to the GAO.

A variety of think tanks and analysts have pegged the cost of repairing and upgrading our transportation networks at somewhere between $200 billion and $262 billion per year over the next decade. The White House’s budget envisions spending an average of about $104 billion per year over that time. Ryan’s budget, meanwhile, allocates $78 billion per year. In his summary, Ryan claims he can meet the country’s needs by cutting back on “imprudent, irresponsible, and downright wasteful spending,” though it’s not clear what waste Ryan has in mind, much less whether it would make up the gap.

Alternatively, we can look at what specific cuts might ensue in the very near future. Third Way has tried to game out the impact of Congress’s recent debt-ceiling deal on specific government programs. The cuts to domestic spending, if applied across the board, would lead to fewer food inspectors, fewer air-traffic controllers, and so forth. And Ryan’s budget, for its part, goes even deeper than the debt-ceiling deal.

Back in March, I asked Third Way’s budget expert David Kendall if he could update some of his numbers for Ryan’s budget. Under Ryan’s plan, for instance, spending on transportation would be 26.1 percent lower in 2014 than it is today. If that size cut was applied to, say, air-traffic control programs, Kendall noted, “there would be 3,092 more flight cancellations and 68,683 delays annually. At the U.S. average of 49 passengers per flight, that’s enough to strand 151,503 more people at the gate and make 3,365,685 more people late every year.”

Likewise, spending on natural resources and the environment would be 14.6 percent lower under Ryan’s budget in 2014 than it is today. Assuming those cuts hit all programs in this category equally — and, again, this is for illustration purposes — then this is how it would affect weather forecasting. “Our weather forecasts would be only half as accurate for four to eight years until another polar satellite is launched,” estimates Kendall. “For many people planning a weekend outdoors, they may have to wait until Thursday for a forecast as accurate as one they now get on Monday. … Perhaps most affected would be hurricane response. Governors and mayors would have to order evacuations for areas twice as large or wait twice as long for an accurate forecast.”

Now, obviously, Ryan’s budget may not lead to these exact cuts. Perhaps Congress will go out of its way to shield weather forecasting while cutting something else in the environmental budget even more. But when the budget is this tight, Congress can’t shield everything. And Kendall’s analysis is a useful way to make those spending reductions a little more concrete.