It’s America’s most popular federal agency, with a favorability rating (74 percent) that would be the envy of any politician, and yet the financially troubled Postal Service is once again the target of a vindictive president.

During this pandemic, the nation has become increasingly dependent on delivery of packages of everything from pet food to toilet paper to life-saving medication. This fall, more and more states — and let’s hope Massachusetts is among them — will depend increasingly on mail-in ballots to safely deliver the 2020 verdict of voters.

Yet the coronavirus outbreak has at the same time exacerbated some longstanding United States Postal Service financial issues — declining first-class deliveries and rising costs. Now, even a $10 billion line of credit contained in the last coronavirus stimulus relief package, and intended to see the agency through the worst economic times since the Great Depression, is at risk.

“The Postal Service is a joke,’’ President Trump said at a recent Oval Office meeting, threatening to withhold the loan funds unless the agency did his bidding. “The post office should raise the price of a package by approximately four times,’’ he demanded.

It’s a gong Trump has rung repeatedly in his ongoing war with Amazon founder Jeff Bezos, who also happens to own The Washington Post, among the president’s least favorite newspapers. It’s true Amazon is a large client of the Postal Service; it’s not true they get some kind of bargain rate, as Trump has also said repeatedly. And raising the rates will not inflict as much pain on the billionaire owner of the retail juggernaut as it will on American families and workers.

A fourfold increase in package rates would probably send much of the Postal Service’s current package delivery business to its rivals FedEx and UPS — something Trump is conveniently ignoring at a time when package delivery service is the USPS’s only growth product. And for consumers, it would mean the cost of mailing a care package or Christmas present would quadruple.

Outgoing Postmaster General Megan Brennan went before Congress just as the pandemic was taking hold looking for some $89 billion in grants and loans to offset lost revenue and including some $25 billion for modernization. Treasury Secretary Steven Mnuchin managed to block all but that $10 billion loan — which has now become Trump’s bargaining chip.

Meanwhile, a new postmaster general has been confirmed and is expected to take office on June 15. He is Louis DeJoy, a North Carolina businessman who has been leading the fund-raising effort for the Republican National Convention scheduled for Charlotte this August. His political ties aside, DeJoy was also president and CEO of New Breed Logistics, which actually supplied the Postal Service with logistics support for some of its processing facilities.

He’s not a creature of the system, like Brennan, who rose from being a letter carrier in Pennsylvania, and that might be a good thing — as long as he doesn’t push to entirely privatize the service. Because while in the short term the Postal Service absolutely needs the aid Trump is blocking, when the dust of this pandemic clears the USPS will have some longstanding issues to deal with. While Trump is way off base calling for a 400 percent increase in package rates, he’s not totally wrong to think that such rates need to be reevaluated — and that the USPS needs to be granted more flexibility to do so.

That was among the recommendations of a presidential task force that concluded in 2018 that “USPS should have the authority to charge market-based prices for both mail and package items that are not deemed ‘essential services.’ ’’

And it noted that “USPS must also address its rising labor and operating costs, including capital expenditures.’’ The last time the service proposed closing post offices was 2012, and the bipartisan primal scream could be heard from coast to coast. But as charming as the tiny Beacon Hill Post Office on Charles Street is, is it really needed when the new and larger Back Bay office is a mere mile away? (The offices in rural areas are, of course, another question.)

This isn’t the best time to make painful decisions about post office branches or personnel — not when more than 2,000 postal workers have been stricken with COVID-19 and at least 46 have died of the illness, and not amid a profound economic downturn and historic unemployment. The Postal Service employs more than 600,000 Americans and serves as a major employer of Black workers and military veterans.

But it would be a good time to get the Postal Service out from under the 2006 congressional mandate that it pre-fund future retiree health care benefits. The House voted to do that back in February, but the bill hasn’t even come up in the Senate. It could make it into the next stimulus package, however, and Senate minority leader Chuck Schumer said he would be looking for more relief for the Postal Service above and beyond the loan that allows Mnuchin —and Trump — to hold the agency hostage.

The Postal Service isn’t simply too big to fail, it’s too important to fail. Today it truly is a lifeline, delivering medicines and masks — and yes, ballots too — to doorsteps across the nation. What it needs now is support, not political hectoring.

Editorials represent the views of the Boston Globe Editorial Board. Follow us on Twitter at @GlobeOpinion.