We have a very clear sense of how House Speaker John Boehner (R-Ohio) wants the next several days to go. In his vision, Boehner will bring his budget proposal to the floor tomorrow; it’ll pass; Senate Democrats will back down and pass it; and President Obama, out of time and options, will put his signature on it. Disaster averted.

It’s an extremely unlikely scenario. Let’s instead consider the more realistic scenarios for the week:

* House defeats Boehner bill: If this happens tomorrow, Senate Majority Leader Harry Reid’s (D) offer gets a significant boost, and would appear to be the last option standing. Senate leaders would immediately try to bring Reid’s plan to the floor, and seek as much GOP support as possible.

* House passes Boehner bill: If this happens tomorrow, Senate Dems, who’ve already pledged to defeat the Speaker’s plan, would use the amendment process to effectively replace its contents with Reid’s counter-offer. The Senate plan would then be to pass the “fixed” version and send it back to the House.

There are all kinds of complications, of course. We don’t know, for example, the extent to which Senate Republicans would delay the process with obstructionist tactics. For that matter, we also don’t know if a filibuster would doom Reid’s bill, even if it’s the last option available. There are, after all, 53 members of the Senate Democratic caucus, some of whom won’t back Reid’s plan (see Sanders, Bernie) because it’s too conservative. Could the Majority Leader’s proposal generate support from, say, 10 Senate Republicans to get over the 60-vote threshold? No one knows.

And what if it does? Whether Boehner’s plan passes the House tomorrow or not, we also don’t know what would happen if the lower chamber were forced to choose: calamity or the Reid plan? House Democratic support would likely be pretty significant — Pelosi has already endorsed Reid’s measure — making passage likely even if only a third of the House GOP caucus supported it. But would a third of the Republican caucus go along to prevent a catastrophe? No one knows this, either.

The Wall Street Journal, meanwhile, reports that some in the West Wing believe the Senate would kill the Boehner plan, and the House would kill the Reid plan, creating the need for a non-existent third alternative to come together very quickly.

At the White House, officials anticipate that neither the Boehner nor Reid plans can get through both houses of Congress, and they are crafting alternatives that could be finalized over the weekend and put to a vote Monday or Tuesday.

They are trying to develop alternatives combining elements of the Boehner and Reid proposals and another from Sen. Mitch McConnell (R., Ky.) so each can claim a measure of victory. The blend could include caps on appropriated spending, a congressional commission to offer further deficit-reduction and a McConnell-style “disapproval mechanism.”

“We have been in regular contact with leaders of both houses and both parties,” White House press secretary Mr. Carney said. “We’re working on plan B.”

Did I mention that Aug. 2 is six days away? And that we blew past Plan B last week and are now eyeing a possible Plan P?

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.