State Sen. Edward J. Pipkin is discovering that being a Republican candidate in Maryland in 2004 could be a lot harder than it was two years ago.

In 2002, the former junk bond trader rode the GOP surge led by Gov. Robert L. Ehrlich Jr. (R) -- and spent more than $500,000 of his own money -- to defeat a powerful committee chairman and claim a state Senate seat from the Eastern Shore.

Last fall, Pipkin began looking for a strategy to topple U.S. Sen. Barbara A. Mikulski (D), who has held public office since her election to the Baltimore City Council in 1971 and won her last two Senate races with 71 percent of the vote. Pipkin aimed to build both on Ehrlich's success and President Bush's respectable poll numbers in heavily Democratic Maryland.

But those assets have evaporated, making an uphill task all the more daunting. Since last fall, Bush's support in the state has dropped. And, at least so far, many of the suburban swing voters and conservative Democrats who backed Ehrlich are sticking with Mikulski.

"If you ask me who the most popular politician in the state of Maryland is, that politician is Barbara Mikulski, hands down," said Patrick Gonzales, a Maryland-based pollster unaffiliated with either campaign. "There is always that chance [for Pipkin], but in politics you look for trends and you look for signs of weakness from the incumbent, a political vulnerability, and I have yet to see it."

Gonzales' survey last month showed Mikulski leading Pipkin 61 percent to 30 percent. The same poll showed Democrat John F. Kerry defeating Bush by 14 points in Maryland in the presidential election. Bush's approval rating in Maryland was 39 percent, down from 47 percent in December.

Gonzales also found that Mikulski not only dominates in traditionally Democratic Baltimore and Montgomery and Prince George's counties, but also polls well in more conservative areas of central Maryland that Ehrlich won in 2002 -- where Pipkin must win decisively to have a chance.

"E.J. needs the president to do well in Maryland, and he needs the Republican base to turn out," said Louis M. Pope, the state's Republican National Committee member.

Pipkin remains undeterred. He plans an aggressive campaign that will include heavy television and radio advertising.

"I am someone who has run a David versus Goliath campaign before," Pipkin said in an interview. "The incumbent has had 27 years to do it her way, so maybe it is time for someone else to step up to the plate with new energy, new ideas and a new focus." (Mikulski won election to the House of Representatives in 1976.)

While GOP leaders concede that Pipkin faces long odds, the feisty Mikulski is on a war footing. She is campaigning hard, touting her membership on the Senate Appropriations Committee as a means of bringing big federal dollars to the state, and her work for seniors, veterans and women's health. She also describes herself as someone willing to stand up for what she believes.

"They've got an open checkbook," she told a crowd recently, referring to Pipkin's wealth. "But I've got an open mouth."

In an interview, Mikulski said Democrats should not underestimate Ehrlich's desire to lead a massive get-out-the-vote effort in the fall to boost Bush in Maryland. She and the Democratic candidates up for reelection this year, she said, will match that effort.

"I am a long-standing grass-roots organizer. I believe you do not wring your hands -- you get out there and organize," Mikulski said.

Pipkin's principal theme in his travels across the state is that Mikulski is out of touch with the major concerns of Maryland voters. The evidence, he says, is what he describes as her support for higher taxes, her failure to help keep high-paying manufacturing jobs from leaving the state, and the pervasive pollution of the Chesapeake Bay.

"Is the Chesapeake Bay better off today than it was when the incumbent came to Washington 27 years ago? The answer is no," Pipkin said.

After earning millions on Wall Street, Pipkin moved to a $1.9 million estate in Queen Anne's County and was active in the successful fight against a plan by then-Maryland Gov. Parris N. Glendening (D) to dump dredged materials into the Chesapeake. He used his new credentials as an environmental activist to challenge state Sen. Walter M. Baker, a 24-year incumbent.

After his victory, Pipkin became a moderate voice in the Senate GOP caucus, frequently bucking party leaders on issues dealing with the environment.

But environmental leaders say Pipkin is going to have a hard time sustaining the charge that Mikulski doesn't care about the environment. They say she has directed tens of millions of dollars of federal aid to the bay.

"It is her vision that made everything possible for us," said Yonathan Zohar, director of the Center of Marine Biotechnology at the University of Maryland, which received a federal grant to breed blue crabs for release into the bay.

Pipkin and GOP leaders said they also plan to portray Mikulski as a liberal who takes what they call extreme positions on some issues, including her support for gun control and her opposition to a bill outlawing some late-term abortions and to Bush's call for a constitutional amendment banning gay marriage.

Yet, Mikulski -- who has a perfect or near-perfect voting record on issues of concern to organized labor, teacher unions and gun control supporters -- has long counted the more conservative parts of the state as a significant part of her political base. In 1998, she won every county except sparsely populated Garrett County.

The daughter of Polish immigrants who, like Pipkin, grew up in the working-class neighborhoods of Baltimore, Mikulski dismisses his "too liberal" charge as "coming from the typical Republican playbook" and "quite stale."

"Barbara Mikulski is 100 percent Maryland," she said in an interview.

And it remains unclear whether Pipkin will be able to raise enough money to counter Mikulski's built-in advantage as an incumbent. Pipkin says he has already put $440,000 of his own money into the race, but refuses to say whether he is willing to invest the millions it would take to run a competitive statewide campaign.

He said campaign finance reports due this month will show that he has raised $350,000 from contributors, more than was raised by Mikulski's past two GOP challengers combined, his campaign says.

Mikulski aides say that they will report more than $2.7 million cash on hand and that they have not begun to deplete their donor base.

Observers are keeping tabs on how much Ehrlich, who polls show remains relatively popular, is willing to campaign for Pipkin. The governor attended a fund-raiser that netted $50,000 last month in Annapolis, and the two met two weeks ago at the governor's office.

Ehrlich, according to GOP leaders present, told Pipkin he needed to "raise his profile" and urged the state senator to show up at his side at gubernatorial events.

But state GOP Chairman John M. Kane said Republicans are leery of having the race become a referendum on the strength of Ehrlich and the party.

"The governor supports E.J., but the governor is very realistic. [Pipkin] has an uphill battle, and everyone knows that," Kane said.

Pipkin is seeking to oust Mikulski, who won her last two races for the U.S. Senate with 71 percent of the vote.Mikulski, rated one of the most popular politicians in the state, plans to campaign hard to retain her seat.