Olympia Snowe and Sandra Fluke don’t have much in common. One is a 65-year-old Republican senator from Maine, the other a 30-year-old feminist law student at Georgetown. But their stories reflect a similar theme: the growing dismay and disgust over the toxic political climate in Washington today.

They also have a common enemy: Rush Limbaugh, the loudmouthed bully who runs one of America’s most popular talk shows. Everyone knows that Limbaugh called Fluke a “slut” and a “prostitute” for arguing that health insurance plans should cover contraceptives. But Snowe is also a victim of Limbaugh’s influence on American politics.

He — and his many clones — have coarsened the political conversation by making insult and invective the common tongue of public discourse. And they enforce a doctrine of conservative purity by branding moderates like Snowe as RINOs (Republicans In Name Only), heretics who should be banished into exile.

Snowe didn’t mention Limbaugh when she recently announced her retirement from the Senate after three terms, but he is a big part of the problem she described: “An atmosphere of polarization and ‘my way or the highway’ ideologies has become pervasive in campaigns and in our governing institutions. … I see a vital need for the political center in order for our democracy to flourish and to find solutions that unite rather than divide us.”

That’s exactly the opposite of what Limbaugh and his friends stand for. They thrive on conflict, division and a black-and-white, us-against-them view of the world.

This polarization is not all on one side. Liberals can play their own purist games, condemning someone like Sen. Bob Casey, a Pennsylvania Democrat, for straying from the party’s pro-choice orthodoxy on abortion. But Rush-ization is more pronounced on the Republican side, where even a straight-laced conservative like former Sen. Bob Bennett of Utah was purged from office for daring to work with Democrats and support government help for the financial industry. Sen. Richard Lugar of Indiana, another conservative who actually believes that Democrats are not demons, is facing a primary challenge from the right on May 8.

Limbaugh is only one factor driving this “my way or the highway” mentality, but as John McCain noted on CBS, “He has influence because he has a strong conservative base.” As a result, many leading Republicans refuse to stand up to him.

House Speaker John Boehner called Limbaugh’s attack on Fluke “inappropriate,” an appalling understatement. Mitt Romney could muster only a feeble rebuke: “It’s not the language I would have used.” Rick Santorum called Limbaugh “absurd” but excused his excesses by saying, “An entertainer can be absurd.”

Those comments are, well, absurd. And cowardly. Conservative columnist George Will got it exactly right when he said on ABC’s “This Week,” “It was depressing, because what it indicates is that the Republican leaders are afraid of Rush Limbaugh.”

It’s time to stop being afraid of Rush Limbaugh, and of the other smokestacks belching pollution into the political atmosphere. It’s time to start fighting back in favor of civility and decency and mutual respect as cornerstones of our politics. We’re not talking about censuring Limbaugh; he has every right to say anything he wants. But others have the right to turn him off, to boycott his advertisers, to make his allies pay a price for their timidity.

Sure, Democrats are trying to exploit his comments — President Obama called Fluke and said later he was thinking about his daughters. “I don’t want them attacked and called horrible names because they are being good citizens,” he told a press conference. But if Republicans cannot count votes, that’s their problem. Obama won the male vote by only one point in 2008 but posted a 13-point margin among women. Voters like Sandra Fluke, unmarried without children, backed Obama over McCain 69 percent to 31 percent. Limbaugh could help enlarge that margin in November.

This episode has caused other brave voices to step forward and reclaim the terrain of civility. David Friend, the head of Carbonite, one of about 20 advertisers to drop the Limbaugh show, said: “No one with daughters the age of Sandra Fluke, and I have two, could possibly abide the insult and abuse heaped upon this courageous and well-intentioned young lady.” John DeGioia, the president of Georgetown, condemned Limbaugh’s “misogynistic, vitriolic” attack and quoted the wisdom of St. Augustine: “Let us, on both sides, lay aside all arrogance. Let us not, on either side, claim that we have already discovered the truth. Let us seek it together as something which is known to neither of us.”

Amen.