The main purpose of this legislation is to prevent the use of federal funds for any construction or renovation projects on the White House grounds during times when the government is not funded, known as a lapse in appropriations. This aims to ensure that taxpayer money is not spent on non-essential projects when the government is facing budgetary issues. Key provisions of the legislation include a clear prohibition on using federal funds for construction or renovation activities at the White House during a lapse in appropriations.