Washington (CNN) - Iowa voters hold Sen. Chuck Grassley in high regard, but the veteran Republican potentially faces a tough re-election in what is shaping up to be a difficult year for incumbents.
Grassley has a favorable rating of 58 percent, according to a new Research 2000 poll conducted for KCCI. But Grassley, first elected to the Senate in 1980, has dropped 21 points over the past few months in a hypothetical match-up against Democratic challenger Roxanne Conlin. The KCCI poll shows that Grassley leads Conlin 49 percent to 40 percent. The telephone survey of 600 likely voters was conducted between May 3-5 and has a margin of error of plus or minus four percentage points.
In past elections, the five-term senator has enjoyed healthy margins of victory. In 2004, Grassley topped his Democratic opponent 70 percent to 28 percent.
But Thursday's poll comes amidst a wave of anti-incumbent sentiment that is so severe it led National Republican Senatorial Committee Chairman John Cornyn of Texas to say earlier this week, "Thank goodness I'm not running this time."
Read the full poll results here.