IS THE DEBATE ON OR OFF?…. For reasons that were never entirely clear, John McCain announced yesterday that he couldn’t spare 90 minutes to attend the agreed-upon presidential debate in Mississippi, scheduled for Friday night. He had to be in D.C. working for the first time in months, doing … whatever it is McCain does.

But that was 24 hours ago, and a breakthrough in Hill negotiations now seems likely. So, McCain can head down to Oxford, Miss., for the debate, right? At this point, that’s still not clear.

John McCain’s campaign expressed cautious optimism Thursday as congressional Republicans and Democrats agreed in principle on a $700 billion bailout of the financial industry hours before the two presidential candidates were to meet with President Bush on the crisis.

Even so, the action didn’t appear to be strong enough to convince McCain to attend Friday’s scheduled presidential debate. His campaign has said he wouldn’t participate unless there was consensus between Congress and the administration, and a spokesman said the afternoon developments had not changed his plans.

“There’s no deal until there’s a deal. We’re optimistic but we want to get this thing done,” McCain spokesman Brian Rogers said.

I’m not sure who “we” refers to, since McCain has had no meaningful role in the negotiations.

Nevertheless, if McCain doesn’t show up, the Obama team apparently plans to host a public event anyway, either fielding questions from PBS’s Jim Lehrer, turning the debate into a town-hall meeting with those in attendance, or some combination of the two.

And that’s precisely why I’m fairly certain McCain will show up for the debate, whether a bailout deal is finalized by tomorrow night or not. Would McCain risk giving Obama this kind of opportunity? I seriously doubt it.

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.