The Cook Political Report changed its rating on Iowa’s fourth Congressional district today from “likely” to “lean” Republican. Although eight-term U.S. Representative Steve King carried this R+11 district by more than 20 points in 2016, several factors make a winning path for Democratic challenger J.D. Scholten seem more plausible than a few months ago, when forecasters moved IA-04 from “safe” to “likely” Republican.

Change Research announced last night that its new survey showed King leading Scholten by just 45 percent to 44 percent. The incumbent quickly released results from an internal poll by WPA Intelligence, showing King ahead by 52 percent to 34 percent, with 11 percent undecided and 3 percent inclined to support a third-party candidate.

FiveThirtyEight.com still gives King a 5 in 6 chance of winning a ninth term, but he could have set himself up much better for next Tuesday. Consider:

Eight-term U.S. Representative Steve King is polling below 50 percent and only six points ahead of his Democratic challenger J.D. Scholten, according to a recent survey commissioned by Scholten’s campaign. Expedition Strategies surveyed 380 “likely 2018 general election voters” in Iowa’s fourth Congressional district between September 5 and September 9 and found 43 percent supported King, 37 percent Scholten. Another 15 percent were undecided, 4 percent backed Libertarian Charles Aldrich, and 2 percent Edward Peterson. The poll’s margin of error was plus or minus 5 percent. Click here for the polling memo; follow me after the jump for more highlights.