Forget that GOP promise of a Balanced Budget Amendment. America’s deficit has soared past last year’s numbers in just 10 months, thanks to Donald Trump’s tax cuts and increased federal spending under his administration.

The budget deficit hit $866.8 billion in the first 10 months of the fiscal year, which began in October 2018, up 27 percent over the same period a year ago.

The figures were detailed in the Treasury Department’s monthly budget report out today.

The new numbers surpassed last year’s budget shortfall, which was $779 billion – a figure that was the largest federal deficit since 2012.

The Republican tax cut passed in 2017, increased federal spending and an aging population were cited as the contributing factors.

The GOP argues, however, that their tax cuts, which went into affect last year, will spur economic growth.

Tax revenue rose 3 percent this fiscal year but that wasn’t enough to keep pace with the 8 percent increase in federal spending.

Earlier this month, Congress – with Trump’s support – passed a two-year budget deal that will increase federal spending on defense and other domestic programs, which will likely add to the budget gap.

Trump vowed to eliminate the federal debt in the 2016 campaign, telling The Washington Post he could get rid of the then-$19 trillion deficit ‘over a period of eight years.’

Instead it has increased under his tenure.

The numbers were released while the president is at his Trump National Golf Club in Bedminister, N.J., where he is spending part of his August.