A federal government shutdown would close some of Washington, D.C.’s most popular attractions and important outposts, but the influence industry won’t even slow down.

Lobbyists are already seeing more work, fielding questions from jittery, or just curious, clients. 

“Everything’s kicked up a notch,” said Jack Howard, a lobbyist with Wexler & Walker Public Policy Associates and a former top aide to then-Speaker Newt Gingrich (R-Ga.) during the last government shutdowns in the mid-1990s. “I find myself spending a lot more time with the Speaker’s office, [Senate Minority Leader] Mitch McConnell’s office. In situations like this, most decisions get elevated to leadership levels.”

Howard’s clients, which include major airlines and energy companies, started calling Monday as they realized just how real the budget impasse on Capitol Hill had become. And it seems just about every business that has some involvement with the government has taken notice. Even companies whose public policy agendas rarely concern the federal budget have become intensely interested in the appropriations process.

“I really didn’t think they were going to get to this point, but in the last 24 hours it’s all anybody’s been talking about,” said Melissa Schulman, a lobbyist with the Bockorny Group. “I have a client that is coming in for some pretty important meetings next week. Their tickets are bought. What are these people supposed to do? We can’t go meet with a government that’s shut down.”

The new Congress has passed two short-term extensions to the budget this year, creating a sense of uncertainty — especially among defense contractors — that has only been exacerbated by the prospect of a shutdown.

“We’ve never lived this before; there’s never not been a defense bill at this stage,” said Michael Herson, a lobbyist with American Defense International who represents several major defense contractors. “We just have to hold our breath here.”

The last government shutdown, which lasted 21 days from Dec. 16, 1995, to Jan. 6, 1996, did not affect military spending because Congress had passed a separate bill funding the Department of Defense in December. The House is expected to vote today on a weeklong stopgap spending bill that includes Defense Department funding for the rest of the year.

For all the politicking, no one will feel the shutdown like federal employees, about 800,000 of whom could be furloughed, according to administration estimates. As a result, the unions representing them have kicked their activities into high gear.

The nation’s largest federal employee union, the American Federation of Government Employees, announced Wednesday that it is suing the Obama administration for failing to provide details on who will work at each agency and how long those “essential” employees can be required to work without pay.

The National Federation of Federal Employees declared Tuesday a national “call-in” day for their 110,000 members around the country.

Not all lobbyists, though, are taking the shutdown threat seriously.

Former Rep. Charlie Stenholm (D-Texas) represents several agriculture clients whose business could suffer if Agriculture Department inspections came to a halt. But Stenholm and his clients are betting that there won’t be a shutdown — at least not yet.

“Like most people in America, they cannot believe that the government is going to shut down over the CR,” he said. “The big battle is going to come in the debt ceiling and the budget for 2012.” 

For many lobbyists, next week — funding or no funding — will be business as usual. Meetings with clients, key federal workers and even some Hill aides are expected to continue.

“We’ll definitely be open — we’re not reimbursed by the government,” said Kelly Bingel, a partner at Mehlman Vogel Castagnetti.

Even if a shutdown occurs, it’s not likely to last long.

“It’s such a temporary stop,” said Kathryn Lehman, a Republican lobbyist at Holland & Knight, who recalled working through the last closure as a House Judiciary Committee aide. “They are just going to take up where they left off, and I will keep working.”

That was Larry O’Brien’s experience back in 1995, too. The veteran lobbyist recalled minimal disruption to his own business during that shutdown.

“The shock factor was fairly high because no one could remember the last time the government shut down,” said the founder of the OB-C Group. “But as far as the practical effect, at least in terms of our world on K Street, I don’t recall that it was hugely unsettling.”

The only change was that it provoked more questions from clients who wanted to know when it would end and how, O’Brien said.

Gerald Cassidy, founder of Cassidy & Associates, a pioneer in the appropriations lobbying business, said the only consequences in the ’95 round were political. He expects a similar outcome should the government close this year.

“If the political tenor of the debate is going to change over the budget shutdown, that could affect clients’ interests,” said Cassidy, a Democrat. “It’s up to the public to determine how they see the shutdown.”