President Barack Obama advocated for filibuster reform, while defending his achievements during his first two years in office, during an appearance on “The Daily Show With Jon Stewart” on Wednesday.

Both parties have used the parliamentary tactic known as the filibuster to block bills in the Senate, Obama acknowledged to the host of Comedy Central’s satirical news show. But Obama said the GOP minority of the 111th Congress has resorted to it more than ever. “That’s just not in the Constitution,” he said. “What we’ve been seeing is unprecedented, and that makes it very difficult for us to move forward.”

Because the Senate’s rules permit unlimited debate, lawmakers have turned to long speeches and other time-consuming tactics, known as filibustering, to sink legislation. To thwart a filibuster, three-fifths of all Senators (60 if there are no vacancies) must vote to invoke cloture, which limits debate. But 60 votes have proved difficult to achieve, and Obama said the process “needs to be changed.”

Republicans filibuster so much legislation that it deters Democrats from working across the aisle, Obama continued, thereby driving the parties further apart.

Republicans have made it “so that I can’t get a deputy financial secretary in the middle of a financial crisis,” the president said. Although the reference may have been metaphorical ­— Deputy Treasury Secretary Neal Wolin was confirmed in May 2009, three months after being nominated — dozens of Obama nominees are awaiting confirmation votes in the Senate.

Several Democrats have expressed support for changing filibuster rules in the next Congress, especially after the chamber was unable to invoke cloture in September on the Defense authorization bill, which included a repeal of the military’s ban on openly gay service members.

In the “Daily Show” interview, Obama also praised Democratic Reps. John Boccieri (Ohio), Betsy Markey (Colo.) and Tom Perriello (Va.), whose re-election campaigns are struggling. Obama said they are “being hammered by negative ads every single day” for “yes” votes on the health care and financial regulatory overhauls.

“Folks took tough votes that they knew were bad politics because they knew it was the right thing to do,” he said. “My hope is that those people are rewarded for taking those tough votes, and if they do, I think we’ll be rewarded on Election Day.”

Obama will stump for Perriello on Friday in the first-term Member’s hometown of Charlottesville, one of the few liberal bastions in what is otherwise a conservative rural district.

The president singled out the same trio in an Oct. 12 town hall meeting for the Democratic National Committee at George Washington University.

Obama defended his legislative achievements when asked by Stewart whether he had aimed too high with his soaring campaign rhetoric.

Although many Democrats in danger of losing their seats in Tuesday’s midterm elections are distancing themselves from the health care overhaul, Obama flaunted the law as a reform on par with the 1935 Social Security Act and the Civil Rights Act of 1964.

“This is what I think most people would say is as significant a piece of legislation as we’ve seen in the country’s history,” Obama said. “It gets discounted because we didn’t get 100 percent of what we wanted.”

He suggested that voters’ expectations may be too high and that they shouldn’t expect him to be able to change the entire system overnight. “It’s not ‘change you can believe in in 18 months,’ it’s ‘change you can believe in,'” he said, referring to his popular 2008 presidential campaign slogan. “‘Yes, we can,’ but it’s not going to happen overnight.”

“My attitude is, if we’re making progress … we are being true to the spirit of the campaign,” he said.

The appearance marked the first time a sitting president has been interviewed on “The Daily Show.” Obama appeared on the program as a Senator in 2007.