Senate Democrats are planning to start the process this week for a Senate vote on a clean debt limit increase, sources tell me — a move that could call the bluff of Republicans in both chambers and force them to take a stand on whether they will allow default and economic destruction if Dems don’t accept their unilateral demands.

The move has the backing of the White House, according to a source familiar with discussions.

The idea is that Senate Dems will move their own clean debt limit bill, rather than wait for the House GOP to hold its own vote on either a clean CR funding the government (which Senate Dems have already passed with broad bipartisan support) or on a debt limit hike. Dems would be challenging Senate GOP moderates to vote for or against averting default and economic havoc outside of any set of conditions House Republicans insist must be attached to any measure raising the debt limit.

Senator John Cornyn is claiming no clean debt limit hike can pass the Senate, but Dems believe there may be at least half a dozen GOP Senators who would be willing to support one. A vote would put that to the test.

The move might also increase pressure on House Republicans. Kevin Smith, a spokesman for John Boehner, tweeted today: “POTUS & his advisers keep calling for a clean debt hike.  So when will his party in the Senate pass one?”

This prompted a response from Harry Reid aide Faiz Shakir: “Will you if we do?”

Now it looks like Senate Dems will do it, though I couldn’t determine when the vote will take place or how long the debt limit extension would last.

If the Senate can pass a clean debt limit increase and send it to the lower chamber, then House Republicans would then presumably refuse to allow a vote on it. With Boehner now claiming a clean debt limit (or a clean CR) cannot pass the House, this would enable Dems to argue Boehner won’t even allow the will of the House to be tested on the debt limit, either, despite the threat of default.

This also raises another question: If Senate Republicans filibuster a debt ceiling hike, will Senate Dem leaders change the rules to allow it to pass by a simple majority, on the argument that so doing is imperative to save the U.S. economy from meltdown? Remember, the deal that averted the “nuclear option” this year left the current rules in place, but Dems reserved the right to act again if GOP obstructionism continued.

The current debt limit brinkmanship provides a particularly stark example of destructive GOP governance at work. Republicans themselves have previously said the debt limit must and will be raised.

Boehner conceded on ABC yesterday that default would result in widespread economic damage. And Cornyn, who is now claiming a clean debt limit hike can’t pass the Senate, had this to say back in January:

“We will raise the debt ceiling. We’re not going to default on our debt…You sometimes try to inject a little doubt in your negotiating partner about where you’re going to go, but I would tell you unequivocally that we’re not going to default.”

And yet, Republicans are now insisting they must be given a wide range of concessions in exchange for avoiding default. If Republicans vote against or filibuster an outcome they themselves say is necessary to avert economic destruction to the whole country — solely because it doesn’t come with unilateral concessions by Dems attached as a condition — it would throw the fundamental absurdity of the GOP position into even sharper relief.

Read more about the debt limit fight:

E.J. Dionne: The shutdown is the tea party’s last stand

Greg Sargent: John Boehner doesn’t want to negotiate

Colbert King: The tea party resurrects the confederacy