The Arkansas Senate race continues to be close and hard-fought. Polling shows the race extremely competitive, and both sides have already spent heavily. Democratic Sen. Mark Pryor has spent almost $900,000 on his re-election bid, while Republican challenger Tom Cotton’s campaign has spent more than $300,000. Outside groups have also been heavily involved.

Pryor has run early ads attacking Cotton’s ambition and selected House votes, as well as TV spots that paint the senator’s values in a positive light to crucial Arkansas voters. Republicans have generally tried to demonize Pryor, but Cotton went up recently with a positive, introductory ad featuring the challenger’s mother.

Each side has boosted the other’s negatives, but Democrats have reason to hope that their initial attempts to define the challenger will make it more difficult for him to make headway against Pryor.

Voters in the state currently are able to make the distinction between President Barack Obama’s record and Pryor’s, and the president’s recent job approval dip didn’t seem to hurt him in Arkansas, where he had hit rock bottom earlier. That’s good news for Democrats who hope that in November voters don’t see Pryor as connected at the hip with the president.

But while Pryor’s campaign is off to a good start and seems to have benefited from a strong, aggressive early effort, the last few months have not been kind to Democrats nationally.

Currently, we seem to be headed toward a typical midterm election, with unhappy voters regarding Election Day as an opportunity to make a statement about the president. With Obama’s job rating in the upper 30s and low 40s in national polls — and lower in Arkansas — Pryor may not be able to swim against a strong Republican current.

Democrats like to point out that Heidi Heitkamp (N.D.) and Jon Tester (Montana) were able to win close, hard-fought Senate races in states that went comfortably for Mitt Romney in 2012, and they argue that those outcomes demonstrated that voters can make distinctions between candidates.

Voters can and do make distinctions, and that is why Pryor has any chance of winning re-election next year. But the difference between 2012 and 2014 (and 2010) is that voters in 2012 had separate votes to cast for president and the Senate in North Dakota and Montana, but next year they will have only one. Given that, the president’s performance can have more of an impact on House and Senate voting decisions in a midterm than in a presidential year.

We don’t now expect 2014 to be as bad for Democrats as 2010 was, but we also don’t expect the midterm election to be as good for Democrats as 2012 was. The makeup of the electorates will be different, and the president’s standing is likely to be lower.

While we continue to regard the Arkansas Senate race broadly as a tossup and think that Pryor is doing all of the right things, we are increasingly skeptical that he can localize the Senate contest as much as he needs to in a state where Obama is so unpopular.

We now believe that there is a better than even chance that as November approaches Arkansas voters will want to make a statement about the president’s performance, and the only way they will be able to do that is by their vote in the Senate race. Unless Pryor can drive Cotton’s negatives through the roof, and prevent his own from going there as well, it will be difficult for the senator to survive, no matter how good a race he runs.

Move from Tossup to Tossup/Tilt Republican in Rothenberg Political Report/Roll Call ratings.