A Des Moines Register poll shows that Gov. Chet Culver (D) is at risk of being a one-term governor in a state that has re-elected every governor -- often multiple times -- since four-year terms were approved in 1972. He's particularly vulnerable against one of his predecessors -- four-term Gov. Terry Branstad (R), who is likely running in 2010.

General Election Matchups
Branstad 57 -- Culver 33 -- Und 8
Vander Plaats 45 -- Culver 37 -- Und 15
Culver 42 -- Rants 35 -- Und 18
Culver 42 -- Fong 34 -- Und 20

In the matchup against Branstad, the Register poll finds that one of five Democrats chose the Republican, as do 58 percent of independent voters. Culver's job approval rating is just 40 percent in the latest poll, far lower than former Democratic Gov. Tom Vilsack ever scored, and a point Branstad hit only briefly in his tenure.

Favorable Ratings
Culver 48 / 46
Branstad 60 / 22
Vander Plaats 24 / 12
Rants 14 / 11
Fong 10 / 6

In the 2010 Senate race, incumbent Charles Grassley (R) is much safer, leading potential Democratic opponent Roxanne Conlin 57-30. He has a 57 percent approval rating, though he scores lowest when asked about his role in the health care debate. Thirty-nine percent give him good marks for that issue, while 49 percent grade him as fair or poor.

The Iowa Poll for the Des Moines Register was conducted by Selzer & Co. from November 8-11, with an overall sample of 800 Iowans and margin of error of +/- 3.5 percent. The gubernatorial and Senate matchups were taken from a sample of 539 likely voters and had a margin of error of +/- 4.2 percent.