HOULTON – U.S. Sen. Olympia Snowe, some have argued, is among of the most powerful and recognizable politicians on Capitol Hill.

When it came to Houlton’s sleepy Market Square one recent morning, there was little room for doubt.

“This is what you call grass-roots campaigning. This is where it happens,” Snowe, 59, of Falmouth, told an eagerly nodding young volunteer who had trailed her for most of the morning toting a campaign sign. “In Maine, people rightly expect it.”

Snowe, it seems, has a good handle on what Maine people expect, if her popularity numbers are any indication. When polled last month, 73 percent of Mainers approved of the job Snowe was doing – putting her in a tie for the most popular senator in the nation.

Those numbers – attributable in part to her reputation as a centrist, pundits say – make her a heavy favorite in her bid to return to Washington.

Although her two opponents – Democrat Jean Hay Bright of Dixmont and independent William Slavick of Portland – say that reputation is undeserved, Snowe is quick to defend it.

“When I tell my colleagues that [my opponents] are calling me a ‘Bush enabler,’ they laugh,” said Snowe who rattled off a list of issues – stem cell research, tax cut extensions, oil drilling in the Arctic, Social Security privatization – on which she has defied the GOP administration.

“I have been the one vote, and I’ve had the pressure put on me and I don’t flinch,” Snowe said. “I feel good if I can come up with something that most people like, not just 51 percent of Congress.”

But bucking the party too often can come with a cost. Snowe has had troubles winning favor among Maine’s social conservatives, who have dubbed her a RINO (Republican In Name Only).

Those troubles became apparent in one sidewalk exchange between Snowe and one man – who, seeing Snowe outside his window – quickly put down his coffee and held up a finger to ask her to wait.

“Are you pro-choice or pro-life?” asked the man, polite but intent, after running outside.

“Pro-choice,” Snowe matter-of-factly offered, seemingly knowing her questioner was not.

“Well, then I can’t vote for you,” he said, telling Snowe he thinks women too often choose abortion for convenience sake.

Snowe listened to the man, politely but firmly offered her thoughts and ended the conversation with a smile and a simple, “We disagree,” before moving to the next storefront.

Since her Capitol Hill tenure began in 1978, Snowe, who serves on the intelligence, finance and small business committees, has made more friends than enemies. She has also gained national attention along the way.

“By and large, it’s because she’s regarded as a serious senator who studies the issue and votes her conscience,” said Larry Sabato of the University of Virginia’s Center for Politics.

Although Snowe’s party is expected to take the hardest hit in the midterm elections, Sabato, like most campaign watchers, predicted Maine’s senior senator would win a third term unscathed.

“In a year of highly competitive races and potential upsets, this is not one,” he said of Snowe’s current contest against Hay Bright and Slavick. “It’s as easy a race as exists in the country.”

For their part, Snowe campaign officials say they take every race seriously. And Snowe’s volunteers eagerly take down names of potential volunteers and welcome the chance to put a campaign sign in the window of a willing business owner.

Before the morning was out, Galen Wilde had a sign inside the glass door of his collectibles shop, Shiretown Coins.

But before he taped it up, Wilde, a longtime Republican, asked Snowe a question she’d already heard at least once during her swing through Market Square.

“What’s happened to our party? It seems to be coming apart,” Wilde said, finding particular fault with the Bush administration for its handling of the increasingly unpopular war in Iraq, which Wilde – and Snowe – initially supported.

Snowe agreeably shook her head and launched into her own harsh evaluation of the Bush administration’s strategy moving forward. She, who serves on the Senate intelligence committee, later encapsulated her comments it in a written statement.

“Staying the course is neither an option nor a plan,” the statement said.

Those sentiments were enough for Wilde.

“I don’t agree with everything you’ve done,” he said, specifically noting her 1999 vote not to impeach President Bill Clinton. “But I do like the way you think, and I will vote for you.”

For more information on Olympia Snowe’s campaign, visit www.olympiasnowe.com.