Pennsylvania Senate race labeled 'toss up' in last-minute shift by top handicapper

Casey's race is now in the same category as Senate races in Michigan, Ohio and Wisconsin. 

The ratings change comes as the presidential election between former President Trump and Vice President Kamala Harris is practically tied in the battleground state. With split-ticket voting becoming increasingly rare, it's very likely that whichever party wins the White House will also win the Senate race. 

Republicans also took a hit in the ratings shifts, with Sen. Deb Fischer's race in Nebraska moved again to demonstrate a quickly developing tight race. The match-up shifted from "Likely Republican" to "Lean Republican." 

Independent candidate Dan Osborn, a union leader and mechanic, has appeared to take Fischer's re-election campaign by surprise with his popularity just weeks from the election. No Democrat candidate was nominated in the race. 

Despite the notable challenge, "we still think the heavy red hue of the state wins out, GOP attacks on Democratic efforts to covertly boost Osborn break through and that Fischer makes it across the finish line," Cook wrote. 

Fischer's re-election bid is now in the same category as Sen. Ted Cruz, R-Texas.