The vice president plans to meet with abortion providers and staff members in Minneapolis, a striking political move that shows how assertive Democrats have grown on the issue.

The appearance at a health center will be the latest leg in a nationwide tour by Ms. Harris, who has emerged as the most outspoken defender of abortion rights in the administration. While White House officials say they have largely reached the limits of their power to protect abortion rights, the issue has emerged as a linchpin of their re-election strategy.