Scott Brown harbors no illusions about the difficulty of being the GOP standard-bearer in the special Senate election to replace liberal icon Sen. Edward Kennedy (D).

“I’m a Republican in Massachusetts, trying to take a seat held by Ted Kennedy,— said the 50-year-old state Senator and lawyer. “Of course, it’s an uphill battle.—

Massachusetts, a state that has legalized gay marriage, passed comprehensive health care reform, flatly refused to abolish the income tax by ballot initiative, and decriminalized simple possession of marijuana, is not usually friendly territory for the standard Republican Party platform. Though the state had 16 years of moderate Republican governors, the party’s 2006 nominee was soundly defeated. The GOP controls only about 10 percent of the seats in both chambers of the Legislature. And whichever Democrat emerges from the four-way primary next week will be the heavy favorite to complete the remainder of Kennedy’s term.

Still, Brown ­— a veteran state legislator who has served three terms in the House and three in the Senate — remains confident.

“Obviously I’m the candidate, so I’m an optimist, but I’m also a realist,— he said in an interview. “I’ve always been the perceived underdog, but I’ve won regardless. I just have to tell you, there’s an energy in this campaign that I’ve never felt before.—

From his home base in Wrentham, an exurb about 30 miles from Boston, Brown is running a campaign that hopes to capitalize on the same kind of populist anger over spending increases and soaring deficits that helped propel Republicans to victories in New Jersey and Virginia. Time and time again, he returns to his theme of being a fiscal hawk.

Though he supported the 2006 Massachusetts health care overhaul, he is disdainful of the reform proposals floating around Washington, D.C. — even if some borrow aspects of the Massachusetts reform model, such as a universal mandate to buy insurance and a public insurance exchange.

“I wouldn’t be opposed to the feds giving us some of that stimulus money to fix our plan, so it can be more competitive. But to think that we’re going to throw our plan out so we can ultimately subsidize other states for their lack of [action] on health care — it’s atrocious,— he said.

The voters, Brown says, “are just outraged by the lack of attention to people’s needs— on both the state and federal level.

He accuses all four Democrats in the race — state Attorney General Martha Coakley, Rep. Mike Capuano, philanthropist Alan Khazei and Boston Celtics co-owner Steve Pagliuca — of being cut from the same cloth. “They’re in favor of a second stimulus. They want higher taxes in some instances. They want to put Massachusetts out of business,— Brown said, adding, “This isn’t JFK’s party anymore.—

Indeed, the first sign that Brown is not running a typical Republican campaign is that the president he invokes the most is not Ronald Reagan, but John F. Kennedy. Two of Brown’s latest radio spots quote Kennedy, with Brown pointing out that JFK called for a reduction in taxes — a policy position he believes Democrats have all but abandoned.

Although Brown is a bona fide conservative on the issues, he’s not a rigid ideologue (and he has become well-known for posing for a series of provocative photos that appeared in Cosmopolitan almost 30 years ago). He’s part of a new generation of Massachusetts Republicans who eschew the litmus tests and the purity fights that are roiling the national party in favor of a more flexible brand of Republicanism.

“As a party, we need to have a larger tent. And we need to have some diversity of ideas,— Brown said. “I’m a fiscal conservative. I’ve never voted for a tax increase. Another Republican may not feel that way. I think it’s shortsighted to have a purity test. I don’t know anyone who is ‘pure.’ We’re hurting ourselves,— he said, referring to an ideological “purity test— proposal floated by the Republican National Committee to qualify for RNC money.

“We need to be reflective of everyone that lives here. I vote on the issues. Not all of them are Republican issues,— Brown added. “I care very strongly about our environment. Since when do the Democrats have a monopoly on the environment?—

The state GOP’s new party chairwoman, Jennifer Nassour, is of a similar mindset.

Like Brown, she de-emphasizes her party’s focus on the social issues that don’t resonate in Massachusetts and instead wants to see her party’s candidates run on basic economic issues. She made waves in Republican circles when she said the Massachusetts GOP would simply avoid the gay marriage debate, leaving the issue up to individual candidates to decide.

“To me, social issues are personal issues. Those are personal views, and we are not legislating here — at least I am not legislating anyone’s personal views,— Nassour said in an interview last spring with the New England gay newspaper the Bay Window, adding, “I have no personal agenda I’m trying to push through other than electing Republicans.—

In an interview with Roll Call, she elaborated, saying the gay marriage issue is settled in her state, and she wants her party to focus on “jobs, the economy and belt-tightening.—

“It’s OK for everyone to come to the table with differing ideas. That’s one of the things that makes America great,— she said.

“I think more importantly, the tides have turned here,— Nassour said. “Candidates like Scott Brown have done great jobs with their field organizations. This weekend alone, Brown’s campaign team had 145 new volunteers that were working. … They placed about 13,000 phone calls. We’ve really done a lot this year.—