Initially I was doubtful, but already a few Republican senators are saying, well, let's see who Obama picks and go from there. Given Obama's almost sure to appoint Sri Whatshisname, I think Obama sees an opening.
This. The Republicans made a big mistake by immediately claiming they'd oppose anyone Obama nominated, regardless of qualifications. Lindsay Graham's "If President Obama nominates a well-qualified liberal, I'll block a vote on him. If Hillary Clinton nominates a well-qualifed liberal, I'll vote for him" (or words to that effect) line is an example of the sort of thing that plays right into the Democrats hands and should make it pretty easy to delegitimize the Republican party's opposition to whomever Obama nominates in the eyes of the general public.
Plus, if this drags on, sooner or later folks like Joe Heck, Kelly Ayotte, and Pat Toomey, etc are gonna be forced to say whether they'd vote for a pro-choice nominee and there is really no good answer to that question for folks like them. Portman is really lucky that Strickland screwed up his own answer to that question badly enough that he probably doesn't have to worry about the Roe vs. Wade issue quite as much as some other Republicans, but Tammy Duckworth is already beating Kirk like a piņata over this issue. Ron Johnson is another one who is quite vulnerable to such attacks (the Republican nominee in Colorado will be too).