; total outlays of the Government of the United States means all expenditures of the Government of the United States from any source; total receipts of the Government of the United States means all tax receipts and other income of the Government of the United States, excluding proceeds from its issuance or incurrence of debt or any type of liability; impoundment means a proposal not to spend all or part of a sum of money appropriated by Congress; and general revenue tax means any income tax, sales tax, or value-added tax levied by the Government of the United States excluding imposts and duties. 7. This article is immediately operative upon ratification, self-enforcing, and Congress may enact conforming legislation to facilitate enforcement. .