A new Congressional Budget Office (CBO) analysis found that repealing the Affordable Care Act, also known as Obamacare or the ACA, would likely leave 19 million Americans uninsured by 2016 and add some $353 billion to the federal deficit over ten years.

This analysis -- the first such study since the major provisions of Obamacare came into effect in 2014 -- complicates Republican efforts to roll back the president's landmark healthcare reforms. The last time the nonpartisan CBO considered the effects of the ACA's repeal, in 2012, it estimated added deficits of $109 billion.

Congressional Republicans complained previously about the way the CBO came to these numbers. Earlier this year, Republicans named Keith Hall to run the CBO and called for a different methodology of computing budget impact. Known as dynamic scoring, the computation takes into account macroeconomic effects stemming from policy changes.

Under that method, the CBO still found deficits accruing to $137 billion over the next decade. 

The news also strikes a blow at one of the leading ways Republicans had hoped to do away with Obamacare. Under a congressional tactic called reconciliation, the GOP could overcome a Democratic filibuster to repeal provisions of the ACA. But for reconciliation to apply, changes must be deficit-neutral. A $137 billion price tag rules the maneuver out.

But Republicans had something to latch on to in the report as well. The economic effects of repealing the ACA would lead to an estimated 0.7 percent increase in output, largely because the bill provides incentives for some people to work less. 

"This law acts as an anchor on our economy by dragging down employment and reducing labor force participation," said Mike Enzi, (R-Wyo.), chairman of the Senate Budget Committee. Largely steering clear of the deficit effects related to repealing the ACA, Enzi said the CBO report "does show that repealing this law will boost nationwide employment and grow the economy." 

The Obama administration announced earlier this year that provisions in Obamacare had added more than 16 million people to the ranks of the insured. States that elected to expand their Medicaid coverage under the bill saw their uninsured rate drop more steeply than those that declined.

But the administration is anxiously awaiting the upcoming decision in King v. Burwell, a Supreme Court case that could endanger subsidies in 36 states. Hinging on a few words in the 2,700-page bill, the Obamacare challenge could put millions of Americans at risk of losing health coverage. A decision in that case is expected in the coming weeks.