Hillary definitely backed off. Probably for the same reasons McCain never put up a fight.
On the issue of Obama's relationship with Bill Ayers, a leader of the communist-revolutionary Weather Underground terror group, she might have backed off a bit because she has her own shady relations with communist terror groups.
1) she helped defend the communist Black Panthers in a murder trial
2) Her husband Bill pardoned members of the Puerto Rican Marxist-revolutionary FALN, and also Weather Underground members Susan Rosenberg and Linda Evans.
"In an interview with the radio show Democracy Now, Rosenberg said that she was "totally and profoundly influenced by the revolutionary movements of the '60s and '70s." She became active in feminist causes, and worked in support of the Puerto Rican independence movement and the fight against the FBI's COINTELPRO program.   She also joined the May 19th Communist Organization, which worked in support of the Black Liberation Army, the Weather Underground and other revolutionary organizations .
Rosenberg was charged with a role in the 1983 bombing of the United States Capitol Building, the U.S. Naval War College and the New York Patrolmen's Benevolent Association, but the charges were dropped as part of a plea deal by other members of her group....."
"Rosenberg's sentence was commuted by President Bill Clinton on January 20, 2001, his last day in office. Her commutation produced a wave of criticism by police and New York elected officials...."
At Yale, Hillary found a new Svengali in the form of left-wing law professor Thomas Emerson, known around campus as "Tommy the Commie." Emerson recruited Hillary and other students to help monitor the trial of the New Haven Nine for civil rights violations. Hillary took charge of the operation, scheduling the students in shifts, so that student monitors would always be present in the courtroom. She befriended and worked closely with Panther lawyer Charles Garry. (5)
Some believe that the enormous pressure exerted by the Left helped ensure light sentences for the New Haven Nine. Whether or not this is true, the punishments were mild.
"Only one of the killers was still in prison in 1977," reports John McCaslin in the Washington Times. "The gunman, Warren Kimbro, got a Harvard scholarship and became an assistant dean at Eastern Connecticut State College. Ericka Huggins, who boiled the water for Mr. Rackley's torture, got elected to a California school board." (6)
Hillary's defenders argue that she played no "significant" role in the New Haven Nine's defense. This is semantic hairsplitting. Obviously, Hillary was less "significant" than Charles Garry or "Tommy the Commie" Emerson. But Hillary served as a trusted lieutenant to these movers and shakers. Moreover, she had a national profile as a campus activist. Hillary was no rank-and-file student protester, as her apologists claim.
Indeed, Hillary's work for the Panthers won her a summer internship at the Berkeley office of attorney Robert Treuhaft in 1972. A hardline Stalinist, Treuhaft had quit the Communist Party in 1958 only because it was losing members and no longer provided a good platform for his activism. (7) "Treuhaft is a man who dedicated his entire legal career to advancing the agenda of the Soviet Communist Party and the KGB," notes historian Stephen Schwartz. (8)
The defense of the New Haven Nine marked Hillary's initiation into the sinister underworld of the hard-core, revolutionary Left. To my knowledge, Hillary has never publicly renounced nor apologized for her role in that movement.
Black Panther Party [BPP] Archives
GEORGE STEPHANOPOULOS: And, Senator [OBAMA], if you get the nomination, you'll have to beat back these distractions.
And I want to give Senator Clinton a chance to respond, but first a follow-up on this issue, general theme of patriotism, in your relationships. A gentleman named William Ayers. He was part of the Weather Underground in the 1970s. They bombed the Pentagon, the Capitol, and other buildings. He's never apologized for that.
And, in fact, on 9/11, he was quoted in the New York Times saying, "I don't regret setting bombs. I feel we didn't do enough." An early organizing meeting for your State Senate campaign was held at his house and your campaign has said you are "friendly."
Can you explain that relationship for the voters and explain to Democrats why it won't be a problem?
OBAMA: George, but this is an example of what I'm talking about. This is a guy who lives in my neighborhood, who's a professor of English in Chicago who I know and who I have not received some official endorsement from. He's not somebody who I exchange ideas from on a regular basis.
And the notion that somehow as a consequence of me knowing somebody who engaged in detestable acts 40 years ago, when I was 8 years old, somehow reflects on me and my values doesn't make much sense, George.
The fact is that I'm also friendly with Tom Coburn, one of the most conservative Republicans in the United States Senate, who, during his campaign, once said that it might be appropriate to apply the death penalty to those who carried out abortions.
Do I need to apologize for Mr. Coburn's statements? Because I certainly don't agree with those, either.
So this kind of game in which anybody who I know, regardless of how flimsy the relationship is, that somehow their ideas could be attributed to me, I think the American people are smarter than that. They're not going to suggest somehow that that is reflective of my views, because it obviously isn't.
CLINTON: Well, I think that is a fair general statement, but I also believe that Senator Obama served on a board with Mr. Ayers for a period of time, the Woods Foundation, which was a paid directorship position.
And, if I'm not mistaken, that relationship with Mr. Ayers on this board continued after 9/11 and after his reported comments, which were deeply hurtful to people in New York and, I would hope, to every American, because they were published on 9/11, and he said that he was just sorry they hadn't done more.
And what they did was set bombs. And in some instances, people died. So it is -- I think it is, again, an issue that people will be asking about.
And I have no doubt -- I know Senator Obama's a good man and I respect him greatly, but I think that this is an issue that certainly the Republicans will be raising.