WASHINGTON —  Here’s a look at why it’s so hard for Republicans and Democrats to compromise on urgent matters of taxes and spending, and what happens if they fail to meet their deadline:



NEW YEAR’S HEADACHE

Partly by fate, partly by design, some scary fiscal forces come together at the start of 2013 unless Congress and Obama act to stop them. They include:

• Some $536 billion in tax increases, touching nearly all Americans, because various federal tax cuts and breaks expire at year’s end.

• About $110 billion in spending cuts divided equally between the military and most other federal departments. That’s about 8 percent of their annual budgets, 9 percent for the Pentagon.

Hitting the national economy with that double whammy of tax increases and spending cuts is what’s called going over the “fiscal cliff.” If allowed to unfold over 2013, it would lead to recession, a big jump in unemployment and financial market turmoil, economists predict.



WHAT IF THEY NEVER AGREE?

If negotiations between Obama and Congress collapse completely, 2013 looks like a rocky year.

Taxes would jump $2,400 on average for families with incomes of $50,000 to $75,000, according to a study by the nonpartisan Tax Policy Center. Because consumers would get less of their paychecks to spend, businesses and jobs would suffer.

At the same time, Americans would feel cuts in government services; some federal workers would be furloughed or laid off and companies would lose government business. The nation would lose up to 3.4 million jobs, the Congressional Budget Office predicts.

“The consequences of that would be felt by everybody,” Federal Reserve Chairman Ben Bernanke has said.



THE TAXES

Much of the disagreement surrounds the George W. Bush-era income tax cuts, and whether those rates should be allowed to rise for the nation’s wealthiest taxpayers. Both political parties say they want to protect the middle class from tax increases.

Several tax breaks begun in 2009 to stimulate the economy by aiding low- and middle-income families are also set to expire Jan. 1. The alternative minimum tax would expand to catch 28 million more taxpayers, with an average increase of $3,700 a year. Taxes on investments would rise, too. More deaths would be covered by the federal estate tax, and the rate climbs from 35 percent to 55 percent. Some corporate tax breaks would end.

The temporary Social Security payroll tax cut also is due to expire. That tax break for most Americans seems likely to end even if a fiscal cliff deal is reached, now that Obama has backed down from his call to prolong it as an economic stimulus.



THE SPENDING

If the nation goes over the fiscal cliff, budget cuts of 8 percent or 9 percent would hit most of the federal government, touching all sorts of things from agriculture to law enforcement and the military to weather forecasting. A few areas, such as Social Security benefits, Veterans Affairs and some programs for the poor, are exempt.

THERE’S MORE AT STAKE

All sorts of stuff could get wrapped up in the fiscal cliff deal-making. A sampling:

• Some 2 million jobless Americans may lose their federal unemployment aid. Obama wants to continue the benefits extension as part of the deal; Republicans say it’s too costly.

• Social Security recipients might see their checks grow more slowly. As part of a possible deal, Obama and Republican leaders want to change the way cost-of-living adjustments are calculated, which would mean smaller checks over the years for retirees who get Social Security, veterans’ benefits or government pensions.

• The price of milk could double. If Congress doesn’t provide a fix for expiring dairy price supports before Jan. 1, milk-drinking families could feel the pinch. One scenario is to attach a farm bill extension to the fiscal cliff legislation — if a compromise is reached in time.

• Millions of taxpayers who want to file their 2012 returns before mid-March will be held up while they wait to see if Congress comes through with a deal to stop the alternative minimum tax from hitting more people.