OVERLAND PARK, Kan. (AP) — Former Republican presidential nominee Mitt Romney plans to campaign for Kansas Senator Pat Roberts in suburban Kansas City next week, the latest national figure working to save the embattled three-term incumbent. Romney is to headline a rally with Roberts next Monday at the Prairie Fire shopping and residential complex in Overland Park. In a statement, Romney calls Roberts "a conservative champion for Kansas." The former Massachusetts governor has also endorsed Senate nominees in battlegrounds such as Romney in recent weeks has stepped back into the limelight, acting as a national GOP leader in a party searching for one. Roberts is facing independent candidate Greg Orman, an Olathe businessman, in what has become a surprisingly competitive race in GOP-heavy Kansas.