With both the Democratic and Republican presidential nominees expected to emerge from a frontloaded primary schedule by early February, if not sooner, Members of Congress in both parties plan on serving as working backdrops for their candidates on the national stage.

Democrats, who have the power to set the agenda, appear to have the upper hand in both helping to amplify their presidential candidate’s positions and in making the case for larger majorities on Capitol Hill. Congressional Republicans, on the other hand, may be able to help their nominee by playing defense against the Democratic strategy, but they also will likely be pulled in different directions by their sitting president and the new candidate.

For more than a year and a half, Democrats on the Hill and on the presidential campaign trail have harped on the overarching theme of “change.” And as the election season heats up, that song will remain the same.

“That meta-message [of ‘change’] is going to be a major theme of this election,” said one Senate Democratic leadership aide. “The specifics, the slogan — that comes later. But what we’ve started to do and what we’ll continue to do is talk about the ways in which Democrats are working to bring about that change.”

And for the presidential candidates, a key tool to delivering that message will come from Congress, particularly the Senate, Democrats said.

“The desire for ‘change,’ which has become the message of all the presidential candidates on our side, dovetails with the reality of the Republican obstruction that we’re dealing with on the Hill,” said one senior Senate Democratic aide. “We’re sort of the running example that the presidential candidate can point to in addition to [President] Bush.”

As they saw their ability to pass major legislation falter last year, both House and Senate Democrats began highlighting what they have said is the “unprecedented” number of filibusters mounted by Senate Republicans in 2007. Republicans, however, have countered that they only blocked legislation because Democrats were attempting to deny them the ability to amend it.

Congressional Democrats say they expect their presidential candidate to echo their charge that Republicans have been the chief obstacles to “change” and forward progress in Washington — particularly when the nominee is campaigning in states with vulnerable Republican Members.

That, in turn, will feed into Congressional Democrats’ argument that they need a more robust majority in order to be the “agents of change” they believe voters want.

Democrats say there already are plenty of examples to cite when they’re talking to voters, such as Congress’ inability to override Bush’s veto of a children’s health insurance bill as well as the stalemate over how or whether to begin scaling back the Iraq War.

“The only way to get change or achieve those goals is to have a Democratic president and more Democrats in Congress,” said one House Democratic leadership aide. The aide added that Democrats will be holding votes throughout the year “to make the point that if you want real progress on these issues, we need more Democrats.”

Still, Democrats cautioned that the level of message coordination between Members and their nominee will depend on the actual nominee.

But one major new proposal Congressional Democrats expect to push alongside their party’s presidential nominee is the notion of an economic stimulus package to beat back what Senate Majority Leader Harry Reid (D-Nev.) has called a “looming recession.”

Plus, Democrats in Congress say they have plenty of real work to do this year, including passing a budget and funding the government, and they plan to focus on that as well. However, they’re not setting high expectations for other legislation.

“People are realistic and don’t think that year two of this session is going to be much different from year one in terms of our ability to meet with success and push things across the finish line,” said one senior Senate Democratic aide. “So the goal is more to set it up for November.”

Meanwhile, Republicans said they would do their best to aid their nominee while also trying to shore up the bona fides of a number of vulnerable incumbents. But they caution that their naturally defensive posture in the minority will make it more difficult.

“I think [Democrats] have a lot more leverage to do messaging votes because they control the agenda,” said one Senate GOP aide. For example, the aide said Democrats would be able to coordinate the rollout of their nominee’s policy proposals with votes on similarly themed legislation.

“It’s difficult in the minority to match the floor operation with the nominee,” the aide said.

But coordinating with their presidential candidate also presents difficulties given the unpopularity of the current president, Bush’s desire to round out his legacy, and the potential need of the GOP nominee to distance himself from Bush administration policies.

“There’s going to be competing pressure from the president and the nominee, whose positions may not always match,” said the Senate GOP aide.

That dynamic already was apparent in 2007. On immigration, for example, Bush pushed hard — and unsuccessfully — for comprehensive reform, while every major GOP candidate other than Sen. John McCain (Ariz.) campaigned against the idea.

However, Republicans are hoping Bush will use the White House to help them to batter Congressional Democrats.

“I think the Bush administration will poke at Congress as much as possible to make [the election] about Congress and to make the Democratic nominee uncomfortable,” said one senior Senate Republican aide.

Additionally, the fact that Republicans will be defending a number of vulnerable seats will force them at times to focus on pushing those Members to the forefront on more parochial issues. “We’ll be helping to promote them as leaders” on certain issues, said the senior Senate Republican aide.