Democrats were swept into power in 2009 vowing to deliver change, but they have found those promises hard to keep and fear next year will prove even more challenging.

Despite having control of the White House and Congress, internal divisions and partisan rifts tripped up Democrats’ early legislative priorities such as health care reform and climate change. And many fear the hangover from 2009 will stretch way into 2010, particularly as the midterm elections loom.

“Health care is likely to exhaust a lot of political will for passing major legislation,— one senior Senate Democratic aide said.

“Whatever political will does remain will definitely disappear by the middle of next year. So any other legislation that requires heavy lifting needs to be done in the early part of 2010 or it probably isn’t getting done.—

Senior House Democratic aides likewise said Members bruised by a series of tough votes will likely want to take it slow next year.

“I personally don’t think there is going to be much of an appetite to do any really contentious, divisive stuff next term,— one aide said. “If we’re smart, I think that we would spend all next year doing three-day workweeks and then go back to the districts and campaign.—

Senate aides said Democrats will be lucky to get a health care bill to the president this year and that the debate over climate change and a cap-and-trade system for limiting greenhouse gas emissions may be punted to early 2010 in the Senate.

A second House leadership aide said next year’s agenda will depend in large part on the success or failure of the 2009 agenda and whether the economy improves.

Significant bills will still be possible “if we get health care done and people feel good about it and the economy is looking up and it’s looking good to be a Democrat,— the aide said.

But the aide said that big spending bills, such as a transportation overhaul, could be in trouble.

“Nobody’s going to want to be spending any money,— the aide said.

In addition to the possibility that the health care and energy battles bleed into next year, a lot of other thorny issues are theoretically getting ready for a big push. After hitting the pause button on hot-button social issues, President Barack Obama and party leaders will face enormous pressure for action on both immigration reform and gay rights. And the simmering war in Afghanistan could explode into intraparty acrimony as the death toll mounts and anti-war liberals step up their opposition.

Immigration reform has been dealt a double blow — a desire on the part of the administration to avoid polarizing social issues and a recession that has millions of Americans out of work.

And while the debate has the potential to increase Democrats’ credibility with the Latino community in what is shaping up to be a tough election year for the majority, it also will have the effect of firing up the GOP’s base.

Having the immigration reform debate in an election year “is one of the great unknowns,— the second senior Senate Democratic aide said. While the aide noted that it’s “definitely something we want to do,— a decision on whether to have the fight will likely depend on how much pressure the Hispanic community puts on Democrats as well as how the overall political landscape looks for the majority, the aide said.

The House has deferred to the Senate on immigration, preferring not to put their Members on the record without the certainty that something will emerge at the end.

The second House aide called the issue “toxic.—

“I just think there is no way Members are going to be comfortable voting for that,— the aide said.

Gay rights groups and lawmakers are also pushing Democrats to take action on their agenda in 2010, including repealing the “don’t ask, don’t tell— law banning gays from openly serving in the military. The gay rights agenda also includes enacting protections against discrimination in the workplace.

Rep. Barney Frank (D-Mass.), one of three openly gay lawmakers, has counseled gay rights groups to focus this year on lobbying and building support among lawmakers in advance of a push next year.

Frank and other gay rights supporters have warned against pushing too quickly, lest a backlash impede the gay rights agenda. That’s what happened in 1993 during the debate over gays serving in the military, resulting in the passage of the “don’t ask, don’t tell— law.

However, gay rights activists lost one of their most potent advocates in the Senate when Sen. Edward Kennedy (D-Mass.) died in August. Kennedy had long pushed a bill to end workplace discrimination. While other Democrats are sure to take up the charge, none is likely to have the same pull with Senate leaders that Kennedy had.

More meat-and-potatoes legislation also could be on tap next year, including the transportation bill and an extension of some of the Bush-era tax cuts, which are set to expire at the end of 2010.

Whether Congress will be able to muster something more significant, such as broader tax reform that cuts rates for businesses while closing loopholes, remains to be seen.

Senate Democratic aides acknowledged that pulling off a large-scale rewrite of the tax code is unlikely, but they said some of the Bush tax cuts would likely be allowed to expire. However, Democrats admit they will probably be looking to walk a fine line on the issue to avoid GOP accusations that they raised taxes in an election year.

Meanwhile, the imperative still exists for rewriting bank and securities regulation after the near-collapse of the nation’s financial system in 2008.

That issue has been put on the back burner for most of 2009 in favor of health care and climate change legislation, but 2010 appears to be the year it will have its day. However, it will be no small task to pull off the kind of massive overhaul lawmakers have been contemplating.

Finally, Social Security reform continues to simmer in the background. The issue has been talked about by the Obama administration as well as top Republicans as a potential area for a bipartisan overhaul. But given the difficulty of passing major legislation in an election year, Social Security reform could instead be kicked to a commission, similar to what happened in President Ronald Reagan’s first term.