In basic negotiation, there is an idea called a ZOPA–a Zone of Possible Agreement, describing the range of deals that might be acceptable to all sides. If there is no ZOPA, negotiation might be a waste of time. 

Greg Sargent, the Washington Post‘s resident liberal blogger, tweeted on Tuesday: “There is NO solution Tea Party Rs would support that would ever be accepted by Obama/Senate Ds. Now, please proceed.” Whether that was because there are no policies in common, or because Obama and the Democrats were determined to reject whatever the Tea Party might accept, was unclear. (The answer could well be both.)

Early on, Speaker of the House John Boehner signaled that he was determined to avoid default. That created a possible ZOPA on the debt ceiling: Republicans might be amenable to a clean debt limit increase if necessary. At the same time, however, GOP leaders indicated that they were prepared to let the Oct. 17 deadline pass because they would insist on the Full Faith and Credit bill as a backstop against default.

Likewise, over the summer, Speaker Boehner seemed to indicate that the House would not block funding to Obamacare. That changed after Sen. Ted Cruz (R-TX) made his stand, whereupon House conservatives were able to convince Boehner to make changes to Obamacare conditions of passing a continuing resolution to fund the government. Meanwhile, President Barack Obama insisted there would be no negotiations, period.

It may be that there is a ZOPA–a very narrow one, basically consisting of condition-free resolutions to fund the government and raise the debt ceiling, with a few minor modifications. The question is whether that ZOPA includes House Republicans. It would seem to include their leaders, but may not include conservative members of the caucus, who could force Boehner to seek the votes he needs on the Democratic side.

Boehner might do so–but only at the cost of his speakership at the next opportunity. So he might, in fact, be unwilling to reach a deal if he cannot bring his caucus along. If so, that would make a deal impossible.