An election forecaster moved Nebraska’s contentious Senate race slightly toward Sen. Deb Fischer’s (R) challenger, Independent candidate Dan Osborn. Sabato's Crystal Ball shifted the Senate contest from “likely Republican” to “leans Republican” on Thursday, referencing the internal polling that shows Osborn being “competitive” with the two-term incumbent.  “Fischer has led by single-digit margins in her own publicly-released internal polling, while Osborn has produced a flood of internal polls showing him leading, most recently a 48%-46% lead in a Change Research poll (interestingly, his leads have been bigger in some of his other released polls),” Sabato's Crystal Ball managing editor Kyle Kondik and associate editor J. Miles Coleman wrote in an update released Thursday.  Kondik and Coleman mentioned the recent involvement of the Senate Leadership Fund (SLF), a super PAC with links to Senate Minority Leader Mitch McConnell (R-Ky.), in the race.  “In recent weeks, SLF has upped its involvement in Senate races that we viewed as more fundamentally marginal—such as Michigan and Wisconsin—so their buy in Nebraska suggested to us that the race there also may be more competitive than Likely Republican,” they wrote.  The shift by the election handicapper comes just a few days after Cook Political Report changed the rating of the Senate contest from “likely Republican” to “lean Republican.” Coleman and Kondik said that if Fischer prevails in November, it could be because “history suggests there won’t be a split Senate verdict in Nebraska.”  “Recall that the aforementioned [Sen. Pete] Ricketts [R] is also up for election this year,” the editors said in the update. “According to an analysis from our former colleague Geoffrey Skelley, 1966 was the most recent cycle that saw a split 'double barrel' Senate outcome.”  Fischer's quest to get reelected in deep-red Nebraska has gotten more competitive, with some in the party expressing frustration that allies have to direct additional resources that could have been utilized in other contests to give the party a better shot at grabbing the upper chamber’s majority heading into the next Congress.  “It’s like some of these safe folks feel a little bit immortal. … It’s what happens in these ruby-red states,” one Senate Republican said this week. “You should always take it seriously in Nebraska.”  “It was muscle memory. 'I haven’t had to worry in the past, why should I have to worry about this now?'” the upper chamber member said, talking about the mentality regarding the matter. “They should have anticipated it.”