Many close aides had been lobbying for the low-risk, nonobjectionable Pawlenty, arguing that the two could run as outsiders taking on Washington…

Instead, Romney went for one of the most prominent faces in Washington. “Do no harm,” the campaign’s longtime philosophy about choosing a ticket mate, had suddenly become: “Let’s take a chance.” For several weeks, top aides had seen that Romney was learning toward bold over safe.

“Chemistry, seriousness, bigness,” one of Romney’s closest advisers said when asked what sealed the deal for Ryan. “Win with a mandate to fix what needed to be fixed.”