CNN

Sen. John McCain, the 2008 GOP presidential nominee, is interviewed by ABC's George Stephanopoulos Sunday.

(CNN) - Sen. John McCain promised Sunday he will work to build consensus in tackling the huge challenges facing the country, and criticized his own party for its latest attack on President-elect Barack Obama.

In his first Sunday political TV appearance since losing the presidential election, McCain rejected complaints from the Republican National Committee that Obama has not been transparent about his contacts with Illinois Gov. Rod Blagojevich.

"I think that the Obama campaign should and will give all information necessary," McCain told ABC's "This Week."

"You know, in all due respect to the Republican National Committee and anybody - right now, I think we should try to be working constructively together, not only on an issue such as this, but on the economy, stimulus package, reforms that are necessary."

McCain's answer came in response to a question about comments from RNC Chairman Mike Duncan. The RNC also released an Internet ad last week, titled "Questions Remain," suggesting Obama is failing to provide important information about potential links between his associates and Blagojevich, who was arrested Tuesday after federal prosecutors accused him of trying to trade Obama's Senate seat for campaign contributions and other favors.

"I don't know all the details of the relationship between President-elect Obama's campaign or his people and the governor of Illinois," McCain told ABC, "but I have some confidence that all the information will come out. It always does, it seems to me."

McCain said he, like Obama and many other lawmakers, believes Blagojevich should resign.

Despite the heated nature of the race, and long lists of attacks in both directions between McCain and Obama, the senator from Arizona emphasized that he plans to focus on pushing lawmakers past partisan politics.

"I think my job is, of course, to be a part of, and hopefully exert some leadership, in the loyal opposition. But I emphasize the word loyal. We haven't seen economic times like this in my lifetime. We haven't seen challenges abroad at the level that we are experiencing, certainly since the end of the Cold War, and you could argue in some respects that they're certainly more complex, many of these challenges. So let's have our first priority where we can work together...

"Will there be areas of disagreement? Of course. We are different parties and different philosophy. But the nation wants us to unite and work together."

Asked whether he ever could have won, given the economy under President Bush, McCain said only that he would "leave that to others, to make that kind of judgment." He pointed out that his poll numbers dropped along with the Dow, but added, "That would sound like I am detracting from President-elect Obama's campaign. I don't want to do that... Nobody likes a sore loser."

The key to moving past the stinging defeat, he said, is to "Get busy and move on. That's the best cure for it. I spent a period of time feeling sorry for myself. It's wonderful. It's one of the most enjoyable experiences that you can have. But the point is: you've got to move on... I'm still a senator from the state of Arizona. I still have the privilege and honor of serving this country, which I've done all my life, and it's a great honor to do so."