In fact, due to the unique structure of the USPS, government shutdowns never touch the mail delivery service.
Since the funding lapses that cause shutdowns only apply to annually-appropriated funding, permanently funded services or services funded through user fees are not affected by the shutdown. So self-sustaining programs, like the Postal Service or passport issuance, or permanently-funded programs, like Social Security, do not get caught up in the budget battle.
The USPS generates most of its own funding through the roughly $70 billion in operating revenue taken in each year from the sale of stamps, cost of shipping, and other operations.
“As an ‘independent establishment of the Executive Branch of the Government of the United States,’ we receive no tax dollars for ongoing operations and have not received an appropriation for operational costs since 1982,” the USPS said in its annual financial filing. “We fund our operations chiefly through cash generated from operations and by borrowing from the Federal Financing Bank (‘FFB’), a government-owned corporation under the general supervision of the Secretary of the Treasury.”
The Postal Service became fully independent in 1971 and drew some congressional funding until 1982, when the USPS was totally weaned off of taxpayer money.
There are also some technical issues related to the way the USPS is treated in the budgeting process, but for the most part the USPS is self-sustaining and not subject to congressional funding squabbles. And while the service has faced some financial issues in recent years, many of those problems were caused by the USPS’s inability to raise prices to stay competitive with the private sector, not the lack of taxpayer money.