WASHINGTON — Confronted with the threat of trillion-dollar-plus deficits for as far as the eye can see, President Donald Trump is offering a $4.8 trillion budget plan for the upcoming fiscal year that rehashes previously rejected spending cuts while leaving Social Security and Medicare benefits untouched.

Trump’s fiscal 2021 budget plan, to be released Monday, isn’t likely to generate a serious Washington dialogue about what to do, if anything this election year, about entrenched fiscal problems that have deficits surging despite a healthy economy.

The new budget, according to senior administration aides and a copy of summary tables, sees a $1.08 billion budget deficit for the ongoing budget year and a $966 billion deficit gap in the 2021 fiscal year starting Oct. 1.

The budget’s most significant policy prescriptions — an immediate 5 percent cut to nondefense agency budgets passed by Congress and $700 billion in cuts to Medicaid over a decade — are nonstarters on Capitol Hill. But the Trump budget is a blueprint written as if Trump could enact it without congressional approval. It relies on rosy economic projections and fanciful claims of future cuts to domestic programs to show that it is possible to bend the deficit curve in the right direction.

The budget would reduce the deficit to $261 billion within a decade if enacted in its entirety and promises balance after 15 years. Trump’s budget blueprint also assumes 2.8 percent economic growth this year and long-term growth averaging 3 percent.

The reality is that no one — Trump, the Democratic-controlled House or the GOP-held Senate — has any interest in tackling a chronic budget gap that forces the government to borrow 22 cents of every dollar it spends.

Trump’s reelection campaign, meanwhile, is focused on the economy and the historically low jobless rate while ignoring the government’s budget.

On Capitol Hill, Democrats controlling the House have seen their number of deficit-conscious “Blue Dogs” shrink while the roster of lawmakers favoring costly “Medicare for All” and “Green New Deal” proposals has swelled. Tea party Republicans have abandoned the cause that defined, at least in part, their successful takeover of the House a decade ago.

Trump and key administration figures had promised that Trump’s signature cuts to corporate and individual tax rates would pay for themselves; instead the deficit spiked by more than $300 billion over 2017 to 2019, falling just short of $1 trillion.

Trump has also signed two broader budget deals worked out by Democrats and Republicans to get rid of spending cuts left over from a failed 2011 budget accord. The result has been eye-popping spending levels for defense — to about $750 billion this year — and comparable gains for domestic programs favored by Democrats.