The Conversation: The Political Pulse

It has been one wild week on Capitol Hill. GOP Sen. Jim Bunning of Kentucky started it off by blocking a bill to extend unemployment benefits. Then Democratic Rep. Charles Rangel of New York stepped down as chairman of the House Ways and Means Committee, pressed by an ongoing investigation into an ethics violation.

Add to that New York Rep. Eric Massa's retirement announcement, which coincided with allegations of misconduct against the Democrat, and it's one drama-filled week in Washington.

In today's Conversation, ABC News' senior congressional correspondent Jon Karl explains to Diane Sawyer what the investigations might mean for the Democrats. Karl also talked with Republican Sen. John McCain of Arizona as part of his "Subway Series," and tried to answer the million-dollar question: "What happened to the old John McCain?"

VIDEO: Diane Sawyer chats with ABCs Jon Karl about Capitol HillPlay

Today's Conversation offers a political roundup you don't want to miss.