“He is the kind of smart, young guy that Mitt likes and Mitt would have probably hired at Bain,” says Mike Murphy, a former Romney adviser. “He shares the intellectual talent and positive outlook of the guys who Mitt mentored for decades.”…

According to Romney insiders, Romney deeply appreciated Ryan’s willingness to privately share his critique of the campaign during the heated Republican primary, where Romney often struggled to make his case. As he watched from afar, long before he endorsed, Ryan drafted a series of detailed strategy and policy advisories, and discussed them with Romney over the phone. For Romney, those corporate-style memos made a lasting impression — and catapulted Ryan into Romney’s circle, where he has remained since.

“Both men are intelligent and very empirically minded, driven by facts,” says Peter Wehner, a friend of Ryan’s and a former Bush and Reagan administration official. “When he looks at Ryan, Romney probably sees somebody like himself, a person he’d want at his side in the business world or the political world. They approach complicated problems the same way.”