Sen. Bernie Sanders on Tuesday evening will hold a virtual town hall with the leaders of America's top postal unions to discuss how to save the U.S. Postal Service as the popular government institution faces the possibility of total collapse without a rapid infusion of funding from Congress.

"The situation is absolutely dire," Mark Dimondstein, president of the American Postal Workers Union (APWU), told New York magazine in an interview last week.

The USPS has been hit hard by the sharp decline in mail volume caused by the coronavirus outbreak. The Postal Service also remains shackled by a congressional mandate requiring the agency to prefund its retirees' health benefits through the year 2056.

"The post office will likely run out of money sometime between July and September of this year," said Dimondstein. "If they run out of money, then the people lose the service."

In addition to Sanders and Dimondstein, National Association of Letter Carriers president Fredric Rolando, National Postal Mail Handlers Union president Paul Hogrogian, and APWU legislative and political director Judy Beard will also be taking part in Tuesday's town hall, which is scheduled to begin at 7:00 pm ET.

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After President Donald Trump threatened to veto the previous coronavirus relief package if it contained direct funding for the Postal Service, progressives are making USPS funding a key priority for the next major Covid-19 stimulus bill.

"We cannot allow Donald Trump to use this horrific pandemic as an opportunity to bankrupt and privatize the Postal Service," Sanders tweeted earlier this month. "Now, more than ever, we need a strong and vibrant postal system to deliver mail 6-days a week. Congress must act now to save it."