LITTLETON, Colo. (AP) - Ann Romney has stepped out into a new role for the final stretch of the campaign: Character witness and defender in chief.

She admonishes her husband's Republican critics. And she tries to convince woman that Mitt Romney is on their side. She also counters the portrait her husband's opponent paints of a soul-less corporate raider.

In the weeks since her big convention debut, she has become the center of a campaign within the campaign.

She has her own charter airplane, holds her own fundraisers, campaigns at her own events, and often sits down for more local interviews than the nominee.

On Monday, she held an event in Henderson, Nev., competing with President Barack Obama, who was in town to prepare for his head-to-head matchup with Mitt Romney.