After self-inflicted wounds from his boasts over decades-old work with segregationist senators and a desultory debate performance, Joe Biden is resetting his campaign to confront his Democratic primary rivals.

The former vice president’s strategy, previewed Wednesday night at a Detroit fundraiser, marks a dramatic shift from the front-runner’s version of a Rose Garden strategy, which was heavy on campaign fundraising and light on taking on his two dozen primary rivals. He is now pledging to attack his rivals head-on, abandoning his nonaggression campaign promise made in May.