I’ve always thought you can learn a lot about someone by the way they act when their guard is down… And I dare say that I may have found something out about Presidential candidates this week as I subjected them to friendly ambushes in a public setting.

At the beginning of the week, nearly all of the Democratic Presidential Hopefuls – Hillary, Obama, Edwards and Richardson – made appearances at the left-leaning Progressives’ annual gathering known as “Take Back America.”

Even Speaker of the House Nancy Pelosi graced the group with her presence – which struck me as odd because she already took it back last year.

Anyways, O’Reilly “Factor” producer Nate Fredman and I set about with a camera crew with a simple task: engage the candidates and invite them on the show with Bill. Mission Accomplished… or sort of accomplished. We got them all on camera – but not all took us up on our offer.

Let’s begin with the Man of Two Americas, John Edwards. We met Edwards at the front door (he does not travel with a security detail) much to his chagrin. Immediately after announcing that I was with FOX News, he turned away in disgust and tried to walk away. But not being one to give up easily, I simply walked away with him in hot pursuit attempting unsuccessfully to get him to even acknowledge my presence. I guess I should expect such treatment from a trial lawyer, but his reaction was really childish and I think for the 11 supporters who were there to cheer him on; it was almost embarrassing for him. So perhaps the saying holds true after all – If he can’t face me, how the heck can he face a terrorist who would seek to do America harm?

We caught Gov Bill Richardson at the door as well. He was just as surprised to see us as Edwards, but Richardson had at least the simple savvy of a politician to stop, collect himself and offer a legitimate answer. Surprisingly, he told me he thought O’Reilly was fair and balanced and he said he’d be delighted to come on the show. Therefore, I think we can safely deduce from his congenial response that he may be a man running for Vice President at this point.

Senator Barrack Obama was by far the best sport of them all. After all, Barack (Code Name: Renegade) Obama now travels with a Secret Service detail so it was a much bigger challenge getting to him.

[Note: The conference took place at the historic Washington Hilton Hotel where after Reagan’s assassination attempt, protected dignitaries enter through a closed garage door entrance.]

But the special protected entrance didn’t stop us – we simply learned the lay of the land and found a weak spot in the route. When we burst through the doors where Obama was doing a VIP handshake line, Renegade smiled, shook my hand and said, “Okay, you guys did this to me once before.” And he even turned to the cameras and said, “Hi Bill.”

Then came our toughest challenge – Sen. Hillary Clinton. Not only does Sen. Clinton travel with a more seasoned security detail, she’s also got the best organizational team of any campaign I’ve ever encountered. And to be quite honest, we weren’t terribly optimistic of our chances for success with her.

Yet the stars aligned and with some sheer dumb luck, we found ourselves back stage in an unsuspecting area just before she walked off stage. Clinton was shocked to say the least when I introduced myself with the cameras rolling and offered her an O’Reilly Factor baseball hat and invited her on the show.

She didn’t take the hat or the offer to come on the show. And she didn’t hang around long to chat either as her security detail quickly got her out of the situation. But she didn’t give me the Edwards treatment either and I actually got a handshake from her. So she gets a middle of the road grade from me.

The only other person we encountered – a guy who ran for President once before – Howard Dean was predictable and honest. When we ambushed him, he simply said “No,” and walked away despite my repeated attempts. And I’ll give him credit; Dean can really walk away fast even when his handlers have no clue where he is supposed to be going.

And oddly enough, Rep. Jack Murtha ran into us because he was lost and looking for directions to the Green Room. When Nate asked him if he wanted to come on the show, Murtha asked back, “Have I been invited?”

To which Nate replied, “Oh, yes sir, many times.” And gathering from the response from the press aide, this did not go over well.

In the end, Obama won the conference’s Straw Poll conducted by Politico.com and I’d say that’s pretty much on par with the Unofficial O’Reilly Ambush Index as well.

We’ll see where that stands a few months from now.

I can be reached for questions or comments or even friendly ambushes at Griffsnotes@foxnews.com.