Fueled by GOP tax cuts for the wealthy and much lower federal tax revenues, the massive United States' federal budget deficit will exceed $1 trillion this year, according to Congressional Budget Office (CBO) estimates released Tuesday. The last time this landmark figure was reached was back in 2012 as the U.S. economy was recovering from the effects of the Great Recession.

The rising deficit continues to alarm some budget experts because deficits typically contract, and don't expand, during periods of sustained economic growth. The $1 trillion deficits under the Obama administration were triggered by the massive economic downturn that began in 2008. In contrast, the Trump administration has presided over rising annual U.S. growth since 2017. The deficit in 2016, former president Barack Obama's last full year in office, came to $585 billion.

CBO expects the budget deficit to average $1.3 trillion from 2021 to 2030, and to increase from 4.6% of GDP to 5.4% over the period. It said this percentage is well above the long-term average since the end of World War II. The U.S. budget deficit hasn't exceeded 4% of GDP for more than five consecutive years, averaging just 1.5% over the period. CBO bemoans the unsustainable spending pattern of the federal government and said the national debt is expected to hit $31.4 trillion by 2030.

The rising annual deficits under Trump means the total debt held by the government should also grow dramatically, from $18 trillion in 2020 to $31 trillion in 2030, according to the CBO. The U.S. government must pay interest on this debt to keep borrowing the money it needs to keep operating.

"The U.S. economy is doing well, with low unemployment and rising wages that have drawn people off the sidelines and back into the labor force," said CBO director Phillip Swagel. "But our projections also suggest that over the long-term, changes in fiscal policy must be made to address the budget situation."

Experts point out deficits at three percent of GDP is still regarded as sustainable. The latest CBO report shows deficits averaging 4.8 percent of GDP over the course of the coming decade.

 The Trump administration reported a $984 billion deficit for the 2019 budget year. On the other hand, CBO expects the U.S. economy to grow by 2.2% in 2020 due to continued consumer strength and a rebound in business fixed investment.

The relentless surge in the deficit follows passage of the 2017 Trump tax cut and jobs act, which has failed to pay for itself with additional economic growth and revenues as promised by Trump.

The CBO figures run counter to recent statements by Trump and other administration officials the 2017 Republican tax cut is creating enough revenue through new economic growth that it will offset all near-term losses. The $1.5 trillion tax cut slashed tax rates for businesses and many households.