His approval rating isn’t soaring in the stratosphere anymore, but Sen. Chuck Grassley (R) is still well-regarded in his state and has a big lead over his likely 2010 Democratic opponent, according to a Selzer & Co. poll conducted Nov. 8-11 for the Des Moines Register.

Grassley has a job approval rating of 57 percent, matching his showing in Selzer’s September survey and exceeding the 54 percent approval rating of Sen. Tom Harkin (D), who was re-elected in 2008.

Though Grassley’s approval rating is down from 75 percent in January, he’s still in a strong early position to win a sixth term in the Senate. In a hypothetical matchup with attorney Roxanne Conlin, Grassley got 57 percent compared with 30 percent for the Democrat. The poll was taken right after Conlin announced she would challenge Grassley.

Conlin, who lost a bid for Iowa governor in 1982 and has not appeared on an Iowa ballot since, is an unknown figure to most state voters. More than six in 10 voters said they could not render either a favorable or unfavorable opinion of her.

The poll showed that Iowans like Grassley mainly for his “honesty— and his “service to Iowans,— though they’re less laudatory about how he has handled health care issues. Grassley is the ranking member on the Finance Committee, an influential panel in the ongoing debate over how to overhaul health care policy.