On July 31, 2005, Montana native Randy Popelka quit his job as a vice-president of Van Scoyoc Associates, a major Washington, D.C., lobbying firm. The next day, he went to work as legislative director for Sen. Conrad Burns, R-Mont.

A study of Montana's two senators -- Democrat Max Baucus and Republican Conrad Burns -- shows that while both lawmakers have lost staff to lobbying jobs and accepted lobbyist donations, only Burns has hired lobbyists for such key positions as legislative director and campaign chairman. He has also started a nonprofit group with lobbyists.

While such practices are perfectly legal, their ethical implications have come under increasing scrutiny in the wake of the Jack Abramoff lobbying scandal.

Lobbyists and lawmakers serve two different masters: Lobbyists are hired by private companies to influence lawmakers, while lawmakers are elected to do the people's work.

While it's relatively common for a staffer to leave a congressional office and become a lobbyist, it's less common to see them return, said Larry Noble, executive director of the Center for Responsive Politics.

Noble said staffers who become company-paid lobbyists do present possible conflict-of-interest issues, hence the one-year prohibition on aides lobbying their former bosses. Those issues are magnified if the staffer returns because "they really are going back and forth between the interest group and the legislative office and bringing a very specific viewpoint with them," he said.

Both Baucus and Rep. Denny Rehberg, R-Mont., recently removed lobbyists who served as treasurers of their fundraising campaign committees to avoid any appearance of impropriety. Burns continues to have a registered lobbyist as chairman of his 2006 re-election campaign.

"It's a huge questionable situation," said Alex Knott, of the Center for Public Integrity, another government watchdog group. "When it comes to lobbying, clients gravitate toward those with connections and being the chairman of someone's campaign is a huge connection because they control the lifeblood of that campaign."

It's not only Washington observers who see a problem with staffers leaving to lobby; senators themselves are becoming aware of the appearance of problems with the common practice. The Senate Homeland Security and Governmental Affairs Committee last week passed a bill that would prohibit senior Senate aides from lobbying any senator for a full year after leaving a Senate office. Currently, they are forbidden to lobby their former bosses for a year, but are free to lobby any other senator.

While Congress will likely tighten some rules on relations between lobbyists and lawmakers this year, lobbyists cite the constitutional right to petition the government, and say they navigate complex legislative issues to help businesses grow and cities, colleges and other groups get the funding they need.

A detailed look at staffers who have left the Montana senators' offices to become lobbyists reveals that they often handle the same issues they worked on while congressional employees.

Sen. Conrad Burns

Helena lawyer and registered lobbyist Mark Baker is heading up Burns' 2006 re-election campaign and served early on as a spokesman for the campaign. Baker is also a former Burns staffer, having worked for the senator off and on since 1989. He left in 1998 as Burns' legislative director

Baker lobbies as part of his own firm, Anderson & Baker law firm in Helena, and with the D.C. firm of Denny Miller Associates.

Anderson & Baker has reported just over $3 million in federal lobbying income since 1999, records show. At least $2 million came from global telecommunications companies such as AT&T and MCI and the National Cable Television Association.

During much of that time, Burns was either chairman or ranking Republican on the Senate Commerce Committee's Subcommittee on Communications, where many laws dealing with telecommunications begin -- and can die. Today, the Communications Subcommittee has been absorbed into the full Commerce Committee, of which Burns is a member.

Since 2002, Baker and his wife have donated $12,500 to Burns or his political action committee, records show.

In 2003, Burns teamed up with Baker lobbying partner Leo Giacometto, Burns' onetime chief of staff, to found a non-profit group called the U.S.-Asia Network, which is run out of Giacometto's Washington, D.C., lobbying firm. Giacometto is listed as a lobbyist for Anderson & Baker and owns his own firm called Gage LLC. He left Burns' office in 1998.

Asked why he has current and former lobbyists working in his office and on his campaign, Burns said in a statement, "I strive to employ the best people for the job, those with the skills and the passion to work on behalf of Montanans."

Randall Popelka worked in Burns' Senate office for seven years on trade, tax and transportation issues before leaving in early 2003. With the lobbying firm Van Scoyoc Associates, the Billings native lobbied for a number of Montana clients including the city of Billings, Billings Clinic and other Billings and Butte companies.

He also lobbied for national groups like the American Small Manufacturers Coalition. Popelka resigned from Van Scoyoc last July and rejoined Burns as legislative director.

Between 2003 and 2005, Popelka donated nearly $5,000 to Burns' election accounts.

Van Scoyoc is Burns' 10th-largest contributor, giving $15,750 between 2001 and 2006, according to the Center for Responsive Politics.

Bozeman lawyer Will Brooke worked as Burns' chief of staff from the end of 2000 to the end of 2003, when he quit to take a job lobbying with the Greenberg Traurig firm.

Months after Brooke went to work for Greenberg Traurig, the lobbying excesses Jack Abramoff while at the firm were revealed. Brooke didn't stay long; by the end of the year, he was registered to lobby for another firm with no connections to Abramoff. He is also registered as a lobbyist with his own firm, the Bozeman-based Brooke Law Firm. Brooke has said he is voluntarily cooperating with federal investigators in the Abramoff probe.

Stan Ullman worked in Burns' Senate office for four years as a legislative assistant before becoming a lobbyist in 2002.

Ullman left Burns to join the lobbying and public relations firm Capitol Associates. He was registered as a lobbyist largely for health and educational institutions until 2004, when he joined Giacometto's firm, Gage LLC.

Ullman last year registered to lobby on his own. His clients included Salish Kootenai College and the Montana Wyoming Tribal Leaders. Burns tried to give the latter group about $100,000 in campaign donations he had received from Abramoff clients, but they refused to take the money.

Shawn Vasell worked with Abramoff at Greenberg Traurig. He quit in 2002 to work as Burns' state director in Montana. After almost a year, he quit Burns' staff and went back to lobbying with Abramoff. Vasell now works as an in-house lobbyist for Hewlett Packard.

Michael Rawson worked in Burns' Senate office for 10 years, from 1995 to 2005. He left Burns to become a lobbyist at Gage, Giacometto's firm.

Giacometto had hired Rawson to work for Burns in 1995, when Rawson started as a systems administrator, according to National Journal. Rawson rose to become a senior policy adviser in 2001 and served as the senator's telecommunications aide. At the time, Burns chaired the Communications Subcommittee.

He is now a registered lobbyist for communications companies including Nextel, MCI Worldcom Corp. and Vonage.

Upon joining Gage, Rawson also took over from Giacometto as the head of the U.S.-Asia Network.

Sen. Max Baucus

A spokesman for Baucus said three staffers have left his office in the last six years to become lobbyists. But Baucus has never hired a lobbyist for his congressional staff, nor has he formed or chaired a non-profit group with lobbyists, the spokesman said.

Asked whether staffers who have left Baucus' office to lobby have any special influence with the senator, Baucus spokesman Barrett Kaiser said, "Absolutely not."

Jay Driscoll worked as a telecommunications legislative assistant in Baucus' senate office for three years. In 2004 the Billings native left to become director of government and regulatory affairs for the Western Telecommunications Alliance's Washington office. He worked as a registered lobbyist for the group.

In early 2005 he became legislative director of the Independent Telephone & Telecommunications Alliance, serving as its chief in-house lobbyist. Records do not show Driscoll giving Baucus any contributions.

Jeff Forbes served as Baucus' chief of staff from 1999 to 2002. He also served as Baucus' top aide in 2003 on the Finance Committee, where Baucus remains the top-ranking Democrat on the panel, which oversees tax and trade issues.

Forbes left in late 2003 to open his own lobbying shop focused on health and trade issues. He joined with two partners to found the Washington, D.C., based Cauthen Forbes & Williams. Forbes lobbies mainly for universities, cities and airlines. He also registered to lobby on tax issues for some clients, including Fannie Mae.

Records show Forbes has given Baucus $2,000 since 2002 and Burns $250.

Zak Andersen, Baucus' former chief of staff, left Baucus' office in 2005 after eight years to lobby. Andersen is now registered to lobby for Microsoft, the sixth-biggest donor to Baucus' war chest between 1999 and 2004, Center for Responsive Politics information shows.

Records show Microsoft hired Andersen to lobby on federal tax issues, which come before the Finance Committee.

Andersen has donated $500 to Baucus, according to campaign finance records.