The Obama Administration recently responded to a petition here calling for an investigation into the tax exempt status of the Westboro Baptist Church, a notoriously politically active yet still tax exempt organization. The Obama Administration, following the policy prescribed here on We the People, refused to get involved in an issue concerning law enforcement.
The organization charged with said investigation is the United States Internal Revenue Service, an institution that's been without an official and permanent head for 242 days as of this petition. The IRS is incapable of doing it's job without a de facto Commissioner, as they've all but given up on enforcing tax code even when the violations are flagrant and obvious.
It's the president's responsibility to appoint a new Commissioner