WASHINGTON -- Now that the elections are over, a lame-duck Congress comes back to work this month to deal with a pile of unfinished business: whether to extend Bush-era tax cuts due to expire, give seniors a $250 Social Security special payment and repeal the military's "don't ask, don't tell" policy against gays serving openly.

It's an open question how much they'll get done.

The current Congress returns Nov. 15 for a post-election session dominated by tax and spending issues. Rarely has such a big pile of work faced lawmakers when the party in power has suffered so much at the ballot box.

Lame duck sessions tend to be notoriously unproductive, especially when there's a turnover in the majority party. The party losing power is in a sour mood and just wants to go home; the party entering power usually prefers to wait until reinforcements arrive in January and wants most business put off so they can put their own stamp on it.

While Republicans easily took over the House and picked up at least six seats in the Senate, the new GOP members won't arrive until January, with the exception of Sen.-elect Mark Kirk, R-Ill. That means Democrats will still command big majorities in the lame duck session.

Lawmakers in both parties, however, are keen to immediately address the looming expiration of Bush-era tax cuts on Dec. 31. Taxes on income, investments, and large estates are set to go up, while the $1,000 per-child tax credit would be cut in half and couples would lose relief from the so-called marriage penalty.

Obama said he would invite both Democratic and GOP leaders to the White House later this month to negotiate over taxes.

"My hope is, is that given we all have an interest in growing the economy and encouraging job growth, that we're not going to play brinksmanship but instead we're going to act responsibly," Obama said.

Extending tax cuts is a top political priority but the world won't end if they expire for a short while: more money will simply be withheld from workers' paychecks. And, next spring's income tax returns are based on tax provisions in effect in 2010.

But there are other items that simply can't be put off until next year.

Not a single spending bill has passed. A stopgap bill is needed to avoid a government shutdown.

Doctors face a 23 percent cut in their Medicare reimbursements, with another 6.5 percent cut looming on Jan. 1. That needs to be fixed.

It gets worse. Tax cuts that expired at the end of last year haven't been extended, and that's a problem that needs to be fixed this year. It would be too late to address it next year because the filing season will have already begun. More than 26 million families would face tax bills in April averaging $2,600 higher because of the alternative minimum tax, or AMT, which was enacted four decades ago to make sure the rich pay at least some tax, but threatens to reach into the middle class because it's never been updated for inflation.

"That's a political train wreck that I can't imagine they'll let happen," said GOP tax lobbyist Ken Kies.

A popular deduction on state and local sales and property taxes has already expired and also needs to be revived this year so taxpayers can claim it when preparing their taxes next year. Also in that category are popular tax breaks on college tuition, the widely backed research and development tax credit and a roster of other business tax cuts.

And, without action by Congress, 2 million unemployed people will lose jobless benefits averaging about $300 a week nationwide by the end of December. It's by no means a sure thing that the benefits could be extended in the post-election session.

One of the few sure bets is that Congress will find a way to avoid a government shutdown when a stopgap spending bill expires Dec. 3. The lame duck session begins Nov. 15 for a week and then resumes after Thanksgiving.

Some lawmakers are holding out the possibility of wrapping all 12 unfinished spending bills for the budget year that began Oct. 1 into a massive $1.1 trillion catchall bill, but that's now a long shot, given the election results. Instead, another stopgap bill freezing budgets at current levels, perhaps until March, is needed to avoid a shutdown.

On the other hand, it's looking bleak for the annual defense policy bill, which has been passed every year for five decades. It's caught in a standoff over the Pentagon's "don't ask don't tell" policy on homosexuals serving in the military.

Here's a look at the rest of the agenda and how it may shake out:

--Taxes: Obama supports renewing most of the Bush-era tax cuts, but not those for family income exceeding $250,000. Emboldened Republicans will insist, however, and with Democrats splintered, many observers think a one- or two-year extension of everything is most likely. Otherwise, it'll fall to the new Congress to decide. Already expired tax cuts, like AMT relief, are likely to get done in the lame duck.

--Medicare physician payments: As they always do, lawmakers are likely to address a 1997 law that's forcing cuts in Medicare's payments to doctors. But it's not clear how long a reprieve the doctors will get.

The there are items that some lawmakers would like to do, but may not be able to:

--Nuclear weapons: Senate Democrats want to ratify the new START treaty between the United States and Russia that would cut each nation's nuclear arsenal by one-fourth.

--Unemployment benefits: Congress has always extended unemployment benefits for the long-term unemployed when the jobless rate has been this high. But it took months earlier this year for Congress to extend jobless benefits through the end of November, and Republicans are likely to insist that any further extension be financed by spending cuts elsewhere in the budget. That could limit any extension to just a couple of months.

--Social Security: Before the election, Democrats promised a vote on legislation to award a $250 payment to Social Security recipients, who are not receiving a cost-of-living hike this year. But the measure failed to garner even a majority in the Senate earlier this year, much less the 60 votes required to beat a filibuster. It won't pass.

--Other leftovers: There's also unfinished legislation on food safety, child nutrition programs. They'll only be able to pass if bipartisan consensus materializes.