That’s not how Barak did it. He did it by strong-arming the caucuses and locking out Hillary supporters. Of course he was also annointed by the leg-tingling press, but he definitely wasn’t a last-minute shoo-in as you describe.
What you describe can happen, but it didn’t happen in 2008.
Wrong! Happened just so! Long before the caucuses.
The first time many of us saw Obama was in still photos of him speaking to a huge crowd, at a free concert, where none of those present knew who he was. Totally orchestrated to introduce him to the voting public. Instant front runner material.
Worked like a charm. And it went so smoothly that many people didn’t know they were herded. As these posts attest.