President Barack Obama’s slumping job approval rating isn’t doing Democrats any favors in the party’s quest to hold a majority in the Senate. But without a handful of Democratic retirements, the Senate likely wouldn’t be in play at all.  

Republicans need a net gain of six Senate seats to get to 51 and control the Senate in the 114th Congress. To make that happen, Republicans will likely need to defeat at least two incumbents, if not three or four. That’s a difficult — but not insurmountable — task, considering Republicans defeated just two Democratic incumbents (both in 2010) in the past four election cycles combined.  

But if a handful of Democratic senators had not chosen to retire this cycle, Republicans would have had a significantly more difficult path to a majority. The retirements of Sens. Max Baucus of Montana, Jay Rockefeller of West Virginia, Tom Harkin of Iowa, Tim Johnson of South Dakota and Carl Levin of Michigan created good — some even great — GOP opportunities.  

A couple of those Democrats may have had a serious test from Republicans in 2014, including Johnson and Rockefeller, but it’s highly unlikely all of them would be in the discussion of competitive races. The senators have a history of winning races in their states, and their re-election bids would have prevented some top Republican candidates from running at all.  

Without those open seats, Republicans would have needed to defeat six incumbents instead of two or three. Historically, that would have been an extremely challenging task.  

Republicans defeated a total of six Democratic senators over the past seven cycles and haven’t defeated more than three in a single cycle since 1980 — when the party knocked off a whopping nine.  

This cycle has the potential for a perfect storm for Republicans, with four Democratic senators running for re-election in states President Barack Obama lost in 2012, and at least three of those are places where he is very unpopular. But Republicans likely won’t need to defeat all of them thanks to the open seats.  

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