The Smithsonian Institution’s Board of Regents voted Monday to undertake a major capital campaign to help raise the $2.5 billion needed to improve and repair its buildings. It is the first large-scale private fund-raising effort in the organization’s history.

Because the Smithsonian gets 70 percent of its $1 billion operating budget from the federal government, raising money from private sources will be a significant departure for the institution.

The plan also promises to be a challenge, given the recent turmoil in the institution’s governance. Its secretary, the top official, resigned last March over expense-account issues. The Smithsonian has been troubled by other controversies, including debate over a $5 million gift from the American Petroleum Institute to the National Museum of Natural History’s Ocean Initiative exhibition hall.