Nodding slowly, Ryan then recited again their list of five priorities — energy, trade, deficit reduction, etc. — even though Wallace’s question was about his tax plan, which he mentioned last. He noted closing loopholes, ending deductions, again not indicating which ones. He assured Morrison that he did have specifics on how the plan would add up, but it’s complicated. “The problem is it just took me about five minutes to go into all of this with you,” Ryan said. “When you are on a 30-second TV show,” he added, “you can’t do as much.”

After the rally, I asked Ryan if he had any regrets about the Wallace interview. “I’m not the kind of guy who has a lot of regrets,” he said, and again he explained his unwillingness to be specific with Wallace as a product of the medium — television — rather than any obfuscation on his part. If anything, Ryan said, his challenge is that he becomes too steeped in details, not that he is unwilling to reveal them. “I get too deep in the weeds too fast, and I start losing people,” he told me. “I had about seven statistics running through my mind when Chris asked me that. And I’m like, If I go through a recitation of all this, it’s going to burn three minutes, and they’re going to change the channel.” Ryan concluded his answer with his standard, “Trust me.” He reassured me: “We can do what we say we’re going to do, we’re very clear about that. I’ve been running numbers on tax-reform proposals for years.”

Skeptics say Ryan owes his superwonk standing as much to comparisons with his colleagues than to any great knowledge or depth. In a recent profile of Ryan by Alec MacGillis in The New Republic, Barney Frank dismissed his colleague’s brainy reputation as being relative to that of other House Republicans, some of whom had just been implicated in a late-night escapade during a Congressional trip to Israel last summer. “He is being graded on a curve,” Frank said of Ryan, “with a bunch of guys who jump into the Sea of Galilee because they want to be closer to God.”

Jared Bernstein, who read Ryan’s fiscal proposals when he worked as chief economist and economic adviser to Vice President Biden, was more pointed regarding Ryan’s credibility. “He definitely talks the talk,” Bernstein told me. “He has a great facility with a particular set of words, like ‘baseline,’ ‘nondefense discretionary’ and things like that.” Bernstein said he eventually came to the view that while Ryan might understand basic concepts, “he does not actually understand what it takes to craft a budget.” This became clear when Ryan was chairman of the House Budget Committee after 2010. “I would say at this point that his budgetary knowledge is a stalking horse for his ideology,” Bernstein told me, meaning that what was important wasn’t the actual balancing of the budget but the slashing of government spending and programs like Medicare and Social Security and the revenue-generating taxes that pay for them. By picking Ryan, Romney signaled that he too was all-in on Big Idea conservatism. And here was the guy, popular with the base and well liked in Congress, who was going to help him sell it to America.

While the notion that Washington operates like a high school has become a cliché, it is an apt one: “No one who ever passed through an American public high school could have watched William Jefferson Clinton running for office in 1992 and failed to recognize the familiar predatory sexuality of the provincial adolescent,” Joan Didion wrote of the former president in “Political Fictions.” In a Rolling Stone profile of John McCain during the 2000 presidential campaign, David Foster Wallace described the then-maverick Republican as a “varsity jock and a hell-raiser whose talents for partying and getting laid are still spoken of with awe by former classmates.” When Ryan actually was in high school — Joseph A. Craig High School, in Janesville — he was the kind who joined a million clubs, befriended teachers and was recognized in his yearbook as his class’s Biggest Brown-Noser. People in both parties described him to me as pleasant and thoughtful and one of the easier members of Congress to get along with. Others have found him arrogant, self-righteous and emblematic of the earnest striver types who populate so many Congressional and White House staffs (and think tanks, policy institutes and lobbying shops), no matter what party is in charge.

Like more or less every politician seeking to stay in the capital, Ryan is quick to express his anti-Washington sentiments. “Not a D.C. guy,” is how he described himself to me in Cincinnati after a soliloquy on Hu-Dey, a Bengals-inspired beer he consumed back in his college days. He sleeps on a cot in his office (its own clichéd symbol of proof of a congressman’s unrootedness), the better to work late, save rent and then return home on weekends to see his family in Janesville.

In fact, Ryan has spent half his life in Washington, arriving right out of college to work in a series of staff jobs before being elected to Congress in 1998, at 28. He met his wife, Janna — who is the first cousin of Representative Dan Boren, a moderate Democrat from Oklahoma — at a party near Washington, in the late ’90s, when she was working as a lawyer and a lobbyist at PricewaterhouseCoopers. He worked closely with Rob Portman in Congress and again years later when Portman served as budget director in the George W. Bush administration; he met Dan Senor in the mid-’90s, when the two were Congressional staff members. A brief foray into the “do you know” game with Ryan quickly yields endless Capitol Hill associations. When the name of my New York Times colleague Carl Hulse, who was a longtime Congressional correspondent, came up, Ryan mentioned that he and Carl get their hair cut by the same stylist (Hanna) at a Capitol Hill salon called Bubbles.