Labor unions and environmental groups that have had little influence during Republicans' control of Washington could suddenly find themselves helping set the legislative agenda if Democrats take control of at least one chamber of Congress.
On the other side, GOP-leaning business groups that won huge policy changes such as lawsuit limits and tax breaks may have to play defense against Democratic proposals for the first time in years.
"We have been out in the cold," said Bill Samuel, the AFL-CIO's legislative director, reflecting on the years since Republicans took control of Congress in 1995 and President Bush captured the White House in 2001.
Access vs. enactment
The Sierra Club knows exactly what it means to be frozen out. When the GOP-led House Resources Committee held hearings, there would be "four panels filled with pro-development interests, and the Democrats would get a token slot in the last panel," recalled Melinda Pierce, the environmental group's chief lobbyist.
A change of leadership in even one chamber would give Democratic-leaning groups improved standing to affect what issues Congress considers. For instance, unions would like to press matters such as stagnant wages and health insurance.
But lobbyists are realistic, noting there is a difference between improved access and getting legislation enacted.
"I wouldn't predict how successful we'll be," Samuel added, noting that Republicans still will hold the White House and that any Democratic majority could be narrow.
Pro-business and conservative groups know a change in Congress could mean playing more defense and scaling back expectations.
Dan Danner, chief lobbyist for the National Federation of Independent Business, said the small-business lobby's work under a Democratic majority would include explaining to federation members that some priorities probably would be harder to achieve.
Some ideas they oppose, such as expanded family medical leave, could surface anew, Danner said.
"We'd have to educate them that it's not that their association isn't working hard or that we're not trying hard to protect their interests, but there are some things that are out of our control," Danner said.
Most lobbyists will adapt
Seasoned firms, trade associations and other special interests have lived through power shifts and know how they would cope with the next one. Many employ lobbyists from both parties.
When political control changes, the most effective lobbyists are those who - even if they lean toward one party - have reached out to lawmakers on both sides, including committee chairmen and top minority leaders, one longtime lobbyist said.
If Democrats win a majority, "if you weren't smart and didn't keep yourself well-balanced, you're maybe going to find yourself not getting your calls returned," said Jim Albertine, former head of the American League of Lobbyists.
A new power shift probably would prove most painful to young Republicans who went from congressional jobs to lobbying and have never known what it is like to be in the minority, Albertine said. But even they could adapt by seeking compromise and reaching out to Democrats while preserving GOP ties, he said.
The National Association of Realtors backs candidates in both parties who support its issues, spokeswoman Mary Trupo said. "So whether it's Democrats or Republicans that are controlling one or both houses of Congress, it doesn't really affect how we do business," she said.
'K Street Project'
After Republicans took control in the mid-1990s, some started a controversial effort to pressure lobbying firms to fire Democratic lobbyists and give solely to the GOP if they wanted access.
Known as the "K Street Project," the effort tracked thousands of lobbyists and their party affiliations, often getting them wrong. It was widely criticized by lobbyists as unfair and crude intimidation.
Ironically, if Democrats win a majority, they may have a lobbyist's work partly to thank for it. The criminal investigation into Jack Abramoff's influence-peddling on Capitol Hill so far has centered on Republicans, giving Democrats an election-year issue with voters.
Washington's influence industry can count on one thing no matter who holds power: Lobbyists will remain coveted fundraisers and donors.
They gave at least $13 million on the federal level this election, roughly 60 percent to Republicans and 40 percent to Democrats, according to the nonpartisan Center for Responsive Politics.
That GOP advantage among lobbyists held even as polls showed Democrats gaining ground going into the final months of election. But lobbyists will have time after the election to increase their Democratic giving.
Many lobbyists who raise money from their clients for candidates would probably extend new help to Democrats. In addition, special interests now solidly Republican in their giving probably would channel at least some additional money to top Democrats.
But unless a Democratic majority is overwhelming and lasts for years, a big decline in GOP giving is unlikely.
Democrats, however, will have one advantage they long have lacked.
"The big thing is they'll have the power to say no to the White House," said Bruce Josten, executive vice president of government affairs for the U.S. Chamber of Commerce.