The fiscal cliff talks that were going so well yesterday have fallen apart, and now Mitch McConnell is reaching out to Vice President Joe Biden to help him see if they can get this deal done. 

Politico and CNN both report from Democratic sources that the talks are stalling because of a Republican provision called "chained CPI," which would alter how much Social Security benefits are given out. The Republicans are insisting it be included in the deal while Democrats are refusing to include it. The Washington Post's Dylan Matthews did a good explainer on chained CPI at the beginning of December when it first was introduced into the negotiations. Apparently the Democrats acknowledge that the President had agreed to include chained CPI during negotiations with John Boehner, but that was only because he had conceded on something else. So because this isn't going to be a grand bargain deal, it's completely off the table. 

Mitch McConnell and Harry Reid acknowledged that talks have hit a wall on the Senate floor shortly after the reports came out. Reid explained they're at an impasse that for some reason won't allow them to continue right now, but said he still thinks there's a chance a deal will get done. "I've had a number of conversations with the president and at this stage we're not able to make a counteroffer," Reid said. "I think that the Republican leader has shown absolutely good faith. It's just that we're apart on some pretty big issues... I'm not overly optimistic, but cautiously optimistic."  

McConnell said he asked Joe Biden to join the negotiations. There’s no single issue that remains an impossible sticking point," McConnell said. "The sticking point appears to be the willingness and interest or frankly the courage to close the deal. I want everyone to know, I’m willing to get this done, but I need a dance partner."

So that's where things stand right now. Biden was in Delaware, but reports are now saying he's at the White House. John Boehner, who has been absent from the latest negotiations, is also in Washington

So that's what's happening. The big boys are being called in to handle this again. 

Update 4:18 p.m.: Republicans have taken chained CPI off the table, so it will be interesting to see where this goes from here.