On The Early Show Tuesday, Brinkley, who's also a CBS News consultant, noted that, "The Amtraks are full. The truck lanes are full. People are riding in, carpooling in, and the city's just swelling.
"I mean, we're trying to make estimates, I think, maybe a month ago. You heard 1 million and 2 million and 3 million. I don't know what it's gonna be, but it couldn't be any more crowded than it is right now.
"And then you have the worldwide audience watching this. This is redefining big inaugural. It's the first global inaugural."
Brinkley says he thinks, of all past inaugural addresses, the one Mr. Obama's is most likely to resemble is John F. Kennedy's "in the sense of ... public service, that it's not just you're here to celebrate Barack Obama the celebrity or the great politician, but he's going to put it back on us. He's going to say, 'All of you out there, I need you. We can't get out of -- this is tough times. But we can do it, but I need your help.
"And so in that way, I think it's going to have echoes of Kennedy. And of course, Franklin Roosevelt in March of 1933 when you had 'nothing to fear but fear itself.'
"What's historic from a media point of view -- as Calvin Coolidge was the first president's inaugural on radio, and then you of course with Harry Truman it went to television. NBC did the Kennedy inaugural parade in color, which was a big break back then. (Bill) Clinton was the first nternet one. This is the first really global TV, Internet, YouTube. Yeah. It's a landmark."
"I think," said Katie Couric, "you're going to be hearing a lot of superlatives today. But I think it's almost impossible to be too hyperbolic about the significance of this moment in our nation's history. If you think about Barack Obama's journey starting in Honolulu, leading him to Indonesia, back to Honolulu, Columbia, Chicago as a community organizer, the first African-American to head the Harvard Law Review. And then, of course, a state senator and then a U.S. senator. And this unlikely journey. I mean, it's really been extraordinary to watch it unfold. And now, as Doug mentioned, there are people from all over the country and really all over the world who are making their own journeys here to witness his."
"It's like a pilgrimagem" Harry Smith observed. "I mean, it really is. Sunday on the mall, talking to all of these people, we just put the camera down and we just talked. And look at the faces. This looks like America. This isn't one party's party, you talk to the people out there, and it's like we're done with -- at least for this moment anyway, they're celebrating this notion of we're done with the partisanship. We're done with the rancor. We really want to see if we can grab hold of this notion of being able to move over that bridge and move beyond all that stuff."
"In fact," Couric pointed out, "58 percent of John McCain's supporters say they're feeling hopeful and optimistic about an Obama administration, a huge number other Americans feeling that way, as well. But, of course, that's juxtaposed with incredible, extraordinary challenges. And I think he's going to have to balance that in today's inaugural address. He's going to have to have inspiration and hope for all these people who are feeling so full of pride with a dose of realism about the hard choices that are going to have to be made and about the sacrifice by every American."
It is the 12th inauguration Bob Schieffer is covering, and he says he's "never seen anything like this. Katie, we were here before the sun came up. By 6:30 this morning -- 6:30 this morning, there were already more than 100,000 people out on the mall. We're going to have more than a million people out there. The biggest inaugural crowd we ever had was for Lyndon Johnson in 1965. This is gonna exceed that. I think the story here today -- we were talking about how big this was going to be -- I think it's gonna be bigger and a larger crowd than anyone anticipated."
"It's going to be a bragging right to say, 'I was in Washington, D.C.," ' Brinkley said, "even if you didn't see Obama, but if you were in Washington for the inaugural, it's gonna mean something down the line.
"I can't help but be moved -- I know everybody is -- by what this means for the country. I mean, we talk about the word freedom, and the freedom struggle, but think about the African-merican community going through the middle passage to slavery, up through the Civil War and emancipation, Jim Crow and then all the history, Booker T. Washington, Rosa Parks, Martin Luther King, and now you have Barack Obama being sworn in as president of the United States."
"Historians," Couric pointed out, "according to the Washington Post, say he is taking command of an office at its historic zenith, a confluence of events that will make him perhaps one of the most powerful presidents in history. It is hard to predict an administration and how successful it will be, but he really is starting off in an enviable position."
"He is," Brinkley agreed, "and it reminds of Franklin D. Roosevelt in 1933 in this regard: The economy was in tatters, Herbert Hoover was an unpopular president. President Bush is not very popular, and he was able to galvanize people with his speech, FDR, move the nation, to fight for all the civil rights and start pushing forward the hundred days of the new deal. And you see echoes of that."
"But the interesting thing," Schieffer said, "is our greatest presidents have always come to us during the worst of times. So, if history is any guide, the pieces are in place for the making of a great president."
Send your pictures, videos and e-mails on Inauguration Day activities to Natali del Conte Tuesday morning, at firstname.lastname@example.org.
If you're on Twitter, you can "tweet" us at Twitter.com/theearlyshow.
To see the CBSNews.com Special Report: Inauguration '09," click here