What must be passed by both houses of Congress and signed by the President for an agency to incur obligations from the U.S. Treasury?

The requirement that must be met for an agency to incur obligations from the U.S. Treasury is the passage of an Appropriations Bill. This bill specifically allocates funds to various government agencies and programs, allowing them to access the necessary financial resources to carry out their operations and projects. The Appropriations Bill details the amount of money each agency can use, effectively giving them the legal authority to spend federal funds.

In the context of the broader budget process, the Authorization Bill is important as it establishes or continues a federal program or agency but does not, by itself, provide the funding required to engage in expenditure. Similarly, while the Defense Budget Resolution may focus on defense-related funding, it is not a standalone document that guarantees appropriated funds as it pertains more specifically to budget outlines rather than delivering that authority. The Federal Spending Act is not a recognized formal process for budget allocation, making it unrelated to the direct obligation of funds from the Treasury.

Thus, only the Appropriations Bill fulfills the necessary legislative condition for allowing agencies to incur obligations, representing a critical step in federal budget execution and financial management.