Media playback is unsupported on your device Media caption Hear how voters in a key swing state are split on the Obama health law

US auditors say the Supreme Court ruling upholding President Barack Obama's health law will save the government $84bn (£54bn) over 11 years.

The Congressional Budget Office (CBO) says most of the savings come from the Supreme Court's decision that states do not have to expand Medicaid programmes.

The CBO also found millions fewer poor people than it previously anticipated would be covered because of the ruling.

And it said that repealing the law would raise the deficit by over $100bn.

The law's combined revenue increases and spending cuts are larger than the cost of expanding coverage, according to the CBO's independent analysts.

The Supreme Court decision in June said that states do not have to broaden Medicaid, a government-sponsored health programme for the poor, as set down in the 2010 law.

Who's uninsured?

Nearly 50 million, or 16.3% of Americans are uninsured

million, or of Americans are uninsured By ethnicity, the rate of those who lack insurance is

15.4% White

White 20.8% Black

Black 18.1% Asian

Asian 30.7% Hispanic

Hispanic Source: US Census Bureau

Although the federal government would pick up the initial cost of that expansion, many states would have to open Medicaid to low-income childless adults for the first time.

Expected opt-outs by conservative-led states such as Texas, Florida and South Carolina are projected to decrease the cost of the expansion over the next 10 years.

However, the CBO also estimates about six million fewer people will be covered by Medicaid by 2022 because of the get-out clause.

Republicans, including presidential candidate Mitt Romney, have warned the law will bloat deficits by trillions of dollars, and they are campaigning for its repeal.

But CBO director Douglas Elmendorf said in a letter to Republican House Speaker John Boehner that overturning the law would actually inflate the deficit by $109bn over a decade.

The office also now projects 30 million people will be uninsured by 2022, up from its previous estimate of 27 million people.

The CBO estimates the number of uninsured in the US is now about 53 million and would grow to 60 million in a decade if the law was repealed.