In a phone call with reporters, Treasury officials predicted a “frustrating season” for taxpayers and tax preparers as a result of delays caused by the pandemic, years of budget cuts to the IRS, and the federal stimulus measures that have added to the tax agency’s workload.

Typically, IRS officials enter filing season with an unaddressed backlog of roughly 1 million returns. This year, however, the IRS will enter the filing season facing “several times” that, Treasury officials said, although they declined to give a more precise estimate.

The IRS closed last filing season with more than 35 million unprocessed returns — a fourfold increase from the last year before the pandemic. As the backlog increased, the IRS also failed to respond to the enormous increase in calls for assistance. Only 9 percent of calls were answered by an IRS customer service representative, while only 3 percent were answered for the 1040 support line for individual income tax returns, according to the National Taxpayer Advocate, a watchdog group….

The pandemic forced the closure of many in-person centers where paper forms are processed, while also affecting the IRS workforce. But even before the pandemic, budget cuts to the IRS forced through by Republicans had led to a roughly 25 percent decline in the size of its staff. And these challenges were exacerbated by the federal response to covid, which required the IRS to implement big new programs — from stimulus payments to the expanded Child Tax Credit — for tens of millions of families.

“By definition, no matter how much more efficient you are, you can’t lose 25 percent of the workforce and assume you can do the same volume of work. It’s a problem across the board — information technology; revenue agents; people answering the phones,” said John Koskinen, who served as commissioner of the IRS under presidents Barack Obama and Donald Trump….