On Tuesday the Congressional Budget Office (CBO) giving estimates about how US budget will look in 25 years stated that the revenue flowing into the federal government will rise, but spending growth will rise even higher than revenue growth.

The CBO in its long-term budget outlook said the country's accumulated public debt could top 100% of gross domestic product by 2040, up from 74% today.

It is said that due to population, rising health costs and rising interest rates, an ever-increasing share of US revenue will go to the country's biggest entitlement programs, including Medicare and Social Security, as well as to interest on the debt.

But it said the federal spending on everything else including the federal government does, from education and defense to research and food safety is estimated to lessen to 6.9% of GDP.

The effect for individuals is that the check they write to the IRS may rise whereas the money the government spends on programs may not pay for as much as it used to.

For instance, CBO estimates that a couple with two kids might pay 16% of their income in federal taxes today. But by 2040, that bite could be 19%.

This will be because their income is more likely to grow but many parameters in the tax code are not indexed for inflation or real income growth, the agency said.

But now the question arises whether there will be any change in tax and spending policies, and if yes whether they will improve or worsen the fiscal outlook.

It said if lawmakers made permanent or further extended temporary tax breaks that would worsen the long-run debt picture.

Politically difficult task for lawmakers will be to decide which ones are worth keeping and which not to. Another tough task will be to decide when and how to curb the long-term growth in accumulated debt.