BOSTON—Massachusetts Sen. John Kerry unleashed a broadside Thursday against Republican "obstructionism," saying the GOP and its talk-show allies have created a "period of know-nothingism" in the country.

With his party braced for defeats in the midterm elections, the 2004 Democratic presidential nominee told the Greater Boston Chamber of Commerce that a Republican machine -- fueled by talk show hosts such as Rush Limbaugh and Glenn Beck -- has undermined progress and misled the public into believing Democrats created the country's current economic problems.

Kerry singled out attacks on an energy deal he was negotiating with Republicans, which fell apart amid criticism of an emissions-trading program. Some 20 Senate candidates are now opposing the proposed deal in their campaigns.

"It's absurd. We've lost our minds," said a clearly exasperated Kerry. "We're in a period of know-nothingism in the country, where truth and science and facts don't weigh in. It's all short-order, lowest common denominator, cheap-seat politics."

To underscore his claim, he said statistics show Republicans had blocked Senate business with filibuster tactics more during the past 18 months than the period between the end of World War I and the Apollo moon landing in 1969.

"The obstructionism is stunning," Kerry said, noting the country still lacks an assistant treasury secretary. "I think America really needs to know more of this kind of tactic and how it's shortchanging us."

Limbaugh and Beck did not immediately respond to e-mails sent to the public addresses on their websites. The Republican National Committee also did not immediately respond to an e-mail or phone message left at its national media office.

The Massachusetts Republican Party accused Kerry of displaying "astonishing arrogance by shifting blame for the failed policies jammed down our throats by his party."

Party Chairwoman Jennifer Nassour added in a statement: "Instead of listening to the concerns of voters upset about the reckless spending that has pushed our national debt to an all-time high; the failed stimulus that has not created jobs and the unpopular government takeover of our health care system that hurts our seniors, Senator Kerry chooses to insult the intelligence of Americans who believe that our country is headed down the wrong path."

During his 45-minute speech, Kerry urged business leaders to support thoughtful candidates. And he urged voters to reject the ones who ignore facts.

He also urged federal support for clean energy and transportation projects, segueing to a defense of Boston's nearly $15 billion Big Dig project to bury the city's main highway in a series of tunnels. It took place over a decade while the city remained open for business.

"We've still got people complaining about the Big Dig, which, in the end, do I think it was over cost? Yes. Do I think it was well-managed? No. But in the end, 20 years from now, people are going to look back on it and they'll still say it was cheap for what we got and they'll try to figure out how they can replicate it," the senator said.

In addition, Kerry pointed out the $700 billion spent on the Troubled Asset Relief Program was requested by a Republican president, George W. Bush.

And he said $80 billion spent on the U.S. auto industry saved it, while the $787 billion economic stimulus program is creating jobs.

"It was not Barack Obama, it was not the Democratic Party. It was not us who asked for a bailout, or created the situation that required a bailout. And it was in response to a Republican president that a lot of Democrats stepped up," he said.

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