By picking Paul Ryan, Mitt Romney got someone who could shore up his conservative credentials. He got someone Catholic. And he made himself look like a political daredevil, which no one had previously mistaken him for.

But Romney was also doing what men of his station tend to do: he was buying the Cadillac. Rightly or wrongly, Ryan commands more reverence within the Republican Party — and generates more buzz — than just about anybody else. He purrs and gleams. And Romney couldn’t resist the leather interior.

Ryan has precisely the kind of styling and clearly defined brand that Romney lacks. It’s striking. From Romney we’ve been given only a fuzzy portrait of how his biography and ideology supposedly converge, of what set him in motion and what makes him tick.

With Ryan it’s the opposite.

Mere days since he loped to the microphone on the U.S.S. Wisconsin, necktie off and cowlick flying high, we have an origin story. When he was 16, his father died, and from the soil of grief and dislocation, a rugged individualism bloomed. He grew up fast and pressed the accelerator on his ambitions, mindful that several generations of Ryan men had died before reaching 60.

We have an intellectual arc. He read (gulp) Ayn Rand. He read Ludwig von Mises. He came to regard capitalism as the handmaiden of self-empowerment and the state as its potential assassin. He came to regard humankind, and presumably himself, in heroic terms.

We have the hobbies that cinematically augment that mind-set. See Ryan in the woods, killing deer with a bow. See Ryan in the lake, catching catfish with his bare hands.

Here he is in his office at midnight, having worked long past dinnertime. There he is in the gym just after dawn, buffing himself into the best specimen possible.

Romney has roots or residences in a half-dozen states and is a steadfast blur, parts of his biography veiled or glossed over, his political passions often hard to divine or to trace to any particular series of events.

Ryan is a laser-sharp postcard from Janesville, Wis., his boyhood and current home. And his background there brims with ripe details — an orchard of anecdotes — that friends and relatives pluck for journalists. At age 6 he burst into “America the Beautiful” while hiking across an especially gorgeous landscape. As a teen he worked the grill at McDonald’s.

Right after Romney announced Ryan, who has positioned himself as the wonk prince of the Republican Party, there was some barbed commentary that Romney had outsourced the policy for his campaign, answering the question of what he really stood for by standing with Ryan.

You could argue that Romney outsourced the emotion, the charisma and the narrative as well. It’s the you-complete-me strategy of vice presidential selection with a steroidal twist: you fill in my overarching blank. And it’s a reminder of how bizarrely colorless Romney’s bid has been.

I say bizarrely not just because modern politics demands some myth-making, some Oprah bait and some unlikely quirks — you’ve no doubt heard by now that Rage Against the Machine and Led Zeppelin are among Ryan’s favorite bands — but because Romney has traveled a vanilla byway before and seen it turn into a rocky road.

That happened in 1994, when he campaigned for the Senate against Ted Kennedy. Although he ultimately lost by 17 points, there were junctures when victory seemed possible, and the mistakes he made “kept him up at night,” wrote Michael Kranish and Scott Helman in “The Real Romney.”

“He had failed to make a compelling enough case for himself, failed in crafting a narrative of his character and convictions that could move voters,” the authors wrote. “Romney told a fellow party member that one thing really ate at him: that one couldn’t sum up in a sentence why he had run.”

Eighteen years later, he isn’t 18 years wiser. That’s reflected in a nonstop chorus of Republican allies urging him to talk more about his Mormonism or his Massachusetts years or Ann Romney’s struggle with multiple sclerosis. They want him to show some skin. They want him to show some soul.

Ryan does that so deftly that the contradictions, holes and hooey in his story recede. Being a Rand devotee and a faithful Roman Catholic is a nifty trick indeed. So is a reputation as a detail-obsessed deficit hawk when your big budget plan lacks crucial details and you spent much of your time in Congress backing George W. Bush’s spending juggernaut.

But Ryan knows how to handle the curves in the road, because he has fine-tuned the most valuable oxymoron in political life: he’s utterly slick in his projection of genuineness.

What Romney stands to gain most from him isn’t a swing state or two. It’s driving lessons.