43 Republicans have signed a letter to Harry Reid saying they will not vote for his plan tonight to increase the debt limit. This dooms passage because of the de facto supermajority requirement needed to move legislation in the United States Senate, something that Democrats could have legislated out of existence at the beginning of the Congressional session.

This actually isn’t as bad as I expected. Olympia Snowe, Susan Collins, Scott Brown and Lisa Murkowski did not sign this letter. That puts Reid only three votes shy of an agreement. In addition, this is a rejection of the original Reid bill. He has time to maneuver to attract those three additional votes. Just as an example, making the Gang of Six plan the trigger would almost certainly attract the three Republican members of the Gang.

However, it’s not so much the raw numbers as the act of sending it my Mitch McConnell that speaks volumes. It means that McConnell is committed to blocking the Reid plan via filibuster. It means that he’s not done extracting concessions. It means that he’s essentially operating on behalf of John Boehner and the House Republicans, who want the maximum possible policies in place before committing to increasing the debt limit. The Senate won’t pass their solution with 60 votes, in all likelihood. It’ll probably take 80-85, with minor falloffs on both sides. That deal can only look worse than it does now, and right now it looks pretty bad.

McConnell appealed to the President to get back involved in the negotiations, since that worked so well the first time.

Democrats conceded that they still lack the votes to repel a GOP filibuster. Reid beseeched his Republican counterpart, McConnell, to join him in reworking the measure so the Senate could pass it and send it back to the House before slumping financial markets open Monday morning.

But in a phone call Friday evening, McConnell told Reid he wanted the White House at the table and expressed frustration that President Obama had rejected an emerging compromise between the two Senate leaders last weekend. Aides said McConnell expected to speak with administration officials Friday night and tamped down talk of an impasse. But Senate Democratic leaders reacted with outrage, accusing McConnell of blocking a deal.

“Unless there is a compromise or they accept my bill, we’re headed for economic disaster,” Reid said.

In addition, the House is poised to vote down the Reid proposal today, and House Armed Services Committee Republicans are opening a new front with their objections to the scale of defense cuts in the Reid plan.

The likelihood of default is pretty high at this stage.

…the House just voted down the original Reid plan, with all 235 voting members of the Republican caucus voting no, joined by 11 Democrats. So even if Reid miraculously got through a version of his plan in the Senate today, I don’t know why we should believe the votes would be there in the House at this stage to approve it.

…Pelosi and Reid have been summoned to the White House. Look to the Senate’s next move for the results of that meeting.

…Mitch McConnell says he spoke to Obama and Joe Biden within the past hour, and that the US “is not going to default for the first time ever.” Default is not the real concern, as there’s ample money in incoming revenue to pay debt service. As Jack Balkin points out the President has already invoked the 14th Amendment, albeit narrowly. He has assured that public debt will be paid off. He has not assured on other payment obligations, all of which are statutory.