I'm just going to borrow the Business Insider headline on this one:
GOP Leader McConnell Already Threatening To Make The US Default
The BI headline puts the issue in its proper perspective, though it should be noted that the story was first dug up by Brian Beutler at TPMDC.
So what's this about? In case you missed my mention of it the other day, the situation is this: the federal debt ceiling needs to be increased in order for the government to be authorized to continue borrowing money. Absent that authorization, when the current statutory debt ceiling is hit, we're looking at government shutdown (as the "mild" side of this) and possible default on the federal debt (as the "spicy" side).
How could it happen? Well, unlike other important pieces of the tangled federal fiscal puzzle like the budget resolution and reconciliation bills, debt ceiling increases aren't protected in any way from our old friend, the filibuster. And the implied threat is that Republicans will filibuster any debt ceiling deal that doesn't somehow guarantee them what they want, meaning they'll force a choice between possible global financial meltdown and giving them their ponies and unicorns -- like repeal of the Affordable Care Act, and maybe some stuff about preventing gay Sharia, or whatever made-up crap they're outraged about this week.
So that's the ultimatum that comes in response to the supposed "Americans want an end to the bickering and for the parties to work together for the good of the country" elections. The old Senate minority, newly converted by national mandate into the new Senate minority, says, "We still haven't won, but do what we say anyway, or we'll kill the global economy."
This, from your staid, "moderate" Senate Republican leader. As opposed to the crazy, de facto Senate Republican leader that the "moderate" guy is holding off from grabbing the reins of (minority) power.