Tense exchanges on Christie; Obama's Chief of Staff takes on Syria and the Keystone Pipeline; Cantor says distrust of the president hurts chances for immigration reform

(CBS News) -- The possible evidence from a one-time ally alleging New Jersey Governor Chris Christie lied about his knowledge of what is being called bridgegate, the closing of key traffic lanes as political retribution, was a key issue on Sunday's Face the Nation. Christie ally former New York City Mayor Rudy Giuliani and John Wisniewski, the New Jersey Assemblyman leading the legislative investigation into the September lane closures on the George Washington Bridge, exchanged tense allegations over the handling of the politically explosive case.

Giuliani took aim at the credibility of Wisniewski, accusing him of a rush to judgment in a case where key details remain uncertain. Wisniewski, he said, is "a guy running the special committee who announces that he believes the governor is lying before he begins the investigation." He added that Wisniewski "should not be running that investigation." When asked by guest host Major Garrett about Giuliani's criticisms of his handling of the case, Wisniewski  fought back, accusing the former mayor of making his own unfounded assumptions. "He's prejudged everything that's been said," Wisniewski said. "What I have said is I have skepticism about the governor's statement. I haven't said that the governor has responsibility for this. I haven't said that the governor knew when this was happening."

Giuliani added that he didn't think the evidence against Christie was legitimate. "So far, there's no evidence to suggest that he's not telling the truth.  I think the governor knows the consequences.  If he's lying, it's a really bad situation.  If he's not lying, then something very unfair is being done to him.  So let's see what happens," he said.

Wisniewski and Giuliani's comments received widespread coverage in the news, including in The Washington Post , CNN, USA Today , Bloomberg Businessweek, The Philadelphia Inquirer, The Wall Street Journal, The New Jersey Star-Ledger, The Guardian, and The Hill.

Also on the broadcast, White House Chief of Staff Denis McDonough discussed a range of issues -- Olympic security, the status of Syria's chemical weapons stockpile and the controversial proposal to build the Keystone XL pipeline. On Friday, the State Department issued a report that appeared to contradict the claims of critics who argued that the oil pipeline project would add significantly to carbon emissions. The pipeline would transport 830,000 barrels of oil a day from Canada to the Gulf Coast, according to The New York Times. But the report claimed that the U.S. will simply extract this oil from other sources if the pipeline is not built. McDonough was vague on the question of whether President Obama would approve its construction. "I'm not going to prejudge that right now," he told Major Garrett during the broadcast. "The president's role is now is to protect this process from politics, let the experts, the expert agencies and the Cabinet secretaries make their assessments both of the study that was put in on Friday as well as its impact on the national interest. So we'll resolve that over the coming period of time." 

Obama's Chief of Staff also addressed questions about security at the Sochi Olympics and expressed confidence that American athletes and visitors would be safe at the games. When asked about Syria's sluggish progress in removing chemical weapons in the wake of a deadly mustard gas attack on Syrian civilians, McDonough conveyed ambivalence at the rate of the disarmament.

"We would like to see it proceed much more quickly than it is, Major. This is a very important development," McDonough said. "We've seen one of the world's largest stock piles of chemical weapons not acknowledged until last summer. Now we're seeing it begin to be secured and dismantled, moved out of the country." McDonough's comments on Face the Nation were picked up by The Wall Street Journal, USA Today, Politico, Reuters, and UPI.

Later on the broadcast, House Majority Leader Eric Cantor addressed the legislative agenda in Congress for the upcoming year, responding to some of the proposals outlined in President Obama's State of the Union address. When asked by Major Garrett about the new GOP proposals for immigration reform, Cantor remained largely noncommittal, emphasizing what he saw as distrust among Republicans of the president's willingness to work in a bipartisan way. "There's a lot of distrust of this administration and implementing the law," Cantor said. "And we just heard the president in his State of Union address say you know what, if he can't work with Congress, he's going to do it his own way. And that sort of breeds this kind of distrust. And I think we're going to have to do something about that in order to see a way forward on immigration."

Cantor did say, however, that he supported a way for children of illegal immigrants to obtain legal status. The majority leader's comments were covered by The New York Times, Politico, The Hill, and The Washington Times.