JUDY WOODRUFF:Now we return to issues here at home and to our interview with retiring Sen. Joe Lieberman, an independent who was the Democratic vice presidential nominee in 2004.

It's the first of several conversations we will have in the coming weeks with members of Congress who are leaving Washington.

I sat down with Lieberman in his hideaway office at the Capitol this morning to talk about the tragedy in his state and more.

Sen. Joseph Lieberman, thank you for talking with us.

SEN. JOSEPH LIEBERMAN,I-Conn.: Judy, good to be with you. Thank you.

JUDY WOODRUFF:At the very moment you are set to retire from the Senate, your state of Connecticut is the site of one of the worst mass shootings in American history, the worst in terms of the age of the victims.

JOSEPH LIEBERMAN:Right.

JUDY WOODRUFF:One of the residents of Newtown said on the NewsHour last night, she said the politicians have failed to protect our children.

Is she right?

JOSEPH LIEBERMAN:Well, I would say that there is reason for people to be angry, skeptical, and cynical about the willingness or capacity of Congress to act to stop mass violence in our country, particularly the part of it that is caused by guns.

Because, look, even after there was the attempted assassination on President Reagan, and his press secretary, Jim Brady, was hit, it was seven years until the Brady Act was adopted.

And that and the assault ban that was adopted around that same time, 1993-'94, are the last real gun control measures that have been adopted. After every previous act of mass violence, shooting, Columbine right through the mall in Oregon last week, really, nothing has been done.

And I don't blame people for being angry. And I hope and I believe I see the beginning of a different reaction here in Washington.

JUDY WOODRUFF:Well, you have called for a national commission. The president today is organizing, announcing a task force.

Is that what you have in mind? And, in fact, as you say, that, again, the residents of Newtown on our program last night were saying, it's—you know, every time there's been a shooting in the past, they said something was going to be done.

JOSEPH LIEBERMAN:Right.

JUDY WOODRUFF:It wasn't done.

JOSEPH LIEBERMAN:Yes.

JUDY WOODRUFF:And they said, we want something done now.

JOSEPH LIEBERMAN:Yes, I don't blame them.

Look, my feeling is that the president, by executive action, Congress, as soon as it can, should do whatever it can do quickly to make it less likely that something like the shootings in Newtown will happen again.

Obviously, I'm talking now about additional gun control laws. I would vote today to restore the assault weapon bans. These are military weapons. There's no need for them in hunting or target practice. I would close the so-called gun show loophole. If you buy a gun at a licensed federal firearms dealer, you have got to go through a background check.

If you buy it at a gun show, you don't. That's ridiculous. The reason I'm proposing a commission is that there are other elements of this that are going to take more time and ought to be part of a national conversation.

For instance, what do you do with a troubled person before they become a killer? What about the impact of violence in the entertainment culture? What should our schools and mental health system be doing to try to find potential murderers before they become murderers?

Those are serious questions that you can't solve overnight. But, in terms of additional gun control legislation, that ought to be done as soon as possible.

JUDY WOODRUFF:Let me ask you about another dilemma, problem facing the Capitol right now, and that's the fiscal cliff.

JOSEPH LIEBERMAN:Yes.

JUDY WOODRUFF:Do you believe it is going to be resolved before Jan. 1, and do you believe that next year there will be a longer-term solution found to deal with spending and taxes?

JOSEPH LIEBERMAN:Right.

I think that what's possible before the end of the year is that we have a substantial down payment on debt reduction. And I'm saying something over a trillion dollars, with a combination of spending reductions, including some reforms to entitlements, and tax increases, particularly on wealthier Americans. That would be a significant accomplishment.

But, frankly, Judy, there are groups in both parties that are pulling at the president and the speaker to keep them from making an agreement. And I hope they will both have the leadership and the courage to make sure that doesn't happen.

JUDY WOODRUFF:Well, speaking of that pulling in both directions, a lot of people today look at this Capitol, this Congress, and they say it's dysfunctional.

Do you believe that dysfunction is just a permanent feature of Congress, or do you think something can be done about it?

JOSEPH LIEBERMAN:No, I think something can be done. I also do want to say, though, I have to say, first, that, of my 24 years here, the last two have been the least productive, because they have been the most uncompromising and most partisan.

But, along the way, in the 22 previous years, we got a lot of things done.

It wasn't a straight line. Sometimes, you would have times of worse partisanship, sometimes less. But I have been privileged to be part of major steps forward on environmental protection, national security, civil rights, human rights, education reform. And every one of those things was bipartisan, particularly in the Senate.

You can't get anything done on a partisan basis in the Senate, because you need 60 votes here to break a filibuster. So, it can and must get better. But, right now, it's at the bottom. It's at the pits, really, and I don't blame people in the country for being angry.

JUDY WOODRUFF:You—when you were recently asked by The New York Times to name, I guess, the three senators you felt the closest to in the Senate, it was three Republicans that you named.

JOSEPH LIEBERMAN:Yes.

JUDY WOODRUFF:So, I—I want to ask you, there's a lot of conversation right now about what does the Republican Party need to do after the terrible losses it suffered in the polls this year.

JOSEPH LIEBERMAN:Right. Right.

JUDY WOODRUFF:Do you have a thought about that?

JOSEPH LIEBERMAN:Well, they need to come back to where the public is. I mean, frankly, they lost touch with that large plurality in the middle of independents.

To me, one of the most fascinating, instructive numbers on the exit polls was that, among self-described moderates, President Obama got 15 percent more votes than Gov. Romney.

So, a lot of people in this country think President Obama is center-left or even far left. But, for self-described moderates, it became a choice between Obama the Democrat, and Romney the Republican. And 15 percent more of them thought that Romney the Republican was too far over to, I would say, the right side.

So I think the Republicans have to come back to where the people are, and they can do it with -- they're particularly out of touch on what I would call social issues.

You might say libertarian issues, personal liberties, and also on matters like immigration.

JUDY WOODRUFF:A word of advice for President Obama for the next four years?

JOSEPH LIEBERMAN:Well, I think President Obama should feel very good about the election, and really should work hard, as I think he's doing now with John Boehner, work persistently and not let himself get discouraged if the Republicans seem to be pushing him off for partisan reasons, because there is so much that he can do, but he will not do it unless he engages some critical mass of Republicans.

And, of course, they have got to be willing to set aside rigid partisanship and ideological purity and come to the middle and compromise with the president to deal with big problems like the debt, like the economy, like cyber-security, like climate change, for instance.

So I hope that will happen. The president, most of all, has the mandate to be a leader. And I will tell you that I think he's off to a good start of leadership since the election. And I felt it the other night in Newtown.

He brought not only comfort to Newtown, Conn. He brought resolve that we're not going to tolerate these kinds of tragedies anymore.

JUDY WOODRUFF:Sen. Joe Lieberman...

JOSEPH LIEBERMAN:Thanks, Judy.

JUDY WOODRUFF:... leaving the Senate after 24 years...

JOSEPH LIEBERMAN:Yes, ma'am.

JUDY WOODRUFF:... thank you.

GWEN IFILL: Joe Lieberman also weighed in on two of his Senate colleagues who may or may not be tapped for the president's Cabinet, endorsing one, but not the other. You can watch the full interview on our website.