(CNN) - Mark Pryor is considered one of the most endangered Democratic senators running for re-election this year, but a new poll has some good news for the two-term Arkansas lawmaker.
According to a non-partisan, live operator survey by the Little Rock-based Opinion Research Associates, Pryor has a 48%-38% lead over Rep. Tom Cotton, his Republican challenger, among registered voters statewide.
While Pryor holds a 10-percentage point advantage – which is right at the edge of the poll's sampling error – it should be noted that the incumbent is under 50%. Thirteen percent questioned in the survey said they were undecided. Political experts generally believe that undecided voters tend to break against the incumbent.
The new poll follows the release earlier this week of another independent survey showing Pryor with a smaller three-point edge over Cotton.
Pryor is running for a third term during what's considered a tough political climate for Democrats. Republicans are tying Pryor to President Barack Obama – who won only 37% of the vote in Arkansas in 2012 – and to Obamacare, which remains very unpopular in the state.
Pryor voted for the health care law.
Making things tougher for Pryor is that unlike in other some other high-profile Senate contests, Republicans are unified behind Cotton, an Iraq war veteran who's considered to be a rising star in the GOP. And Pryor is facing an onslaught of negative television ads mostly from pro-Republican outside groups.
Pryor's re-election bid comes four years after fellow Arkansas Democrat Blanche Lincoln lost her Senate re-election bid by over 20 points. But unlike Lincoln, Pryor, the son of a former senator and governor, does not face a divisive primary challenge.
Pryor's also getting an assist from some pro-Democratic outside groups.
Cotton, meanwhile, has come under attack for his vote against the Farm Bill.
And since this is Arkansas, don't rule out help for Pryor from former President Bill Clinton, who remains popular in his native state.
The Cook Political Report, one of the top non-partisan political handicappers, rates the race as a "toss-up," along with another top handicapper, the Rothenberg Political Report, which rates the contest as "toss-up/tilt Republican."
The results this November in Arkansas' Senate race could decide the fate of the chamber. Democrats hold a 55-45 majority in the Senate (53 Democrats and two independents who caucus with the party), but are defending 21 of the 36 seats up in November, with half of those Democratic-held seats in red or purple states, like Arkansas.
The Opinion Research Associates poll was conducted April 1-8, with 400 registered voters in Arkansas questioned by telephone. The survey's overall sampling error is plus or minus five percentage points.