Public Policy Polling’s latest Iowa survey shows Mark Jacobs with a small lead over the rest of the Republican field in the U.S. Senate race. Democrat Bruce Braley leads all the major Republican contenders, but by a smaller margin than he did last July. Click here for complete results, including question wordings and cross-tabs. PPP surveyed surveyed 869 Iowa voters, including 283 Republican primary voters, between February 20th to 23rd, producing a margin of error of +/- 3.3 percent for the statewide poll and 5.8 percent for the Republican primary findings.

The GOP Senate candidates are still largely unknown, even to Republican voters, but Jacobs has the highest name recognition, thanks to radio and television commercials his campaign has been running since early December. Among PPP’s Republican respondents, 42 percent were undecided, followed by 20 percent for Jacobs, 13 percent for State Senator Joni Ernst, 11 percent for former U.S. Attorney Matt Whitaker, 8 percent for Sam Clovis, and 3 percent each for Paul Lunde and Scott Schaben.

Among the full sample, Braley has the highest name recognition but is still unknown to nearly half the respondents. He leads Whitaker by 40 percent to 34 percent, Ernst and Jacobs by 41-35, and Clovis by 42-34. In PPP’s July 2013 survey, Braley’s lead averaged 11 points. The polling firm’s Tom Jensen argued that the “pretty clear reason” for the tightening in the Senate race is that “Barack Obama’s approval rating in the state has dropped a net 10 points compared to the summer.”

Earlier this month, Jacobs’ campaign released partial results from an internal poll showing Jacobs leading the Republican field for the primary, with 22 percent support compared to 11 percent for Ernst, 8 percent for Whitaker and 6 percent for Clovis. Jacobs’ poll, conducted by Hill Research Consultants, found Jacobs and Braley essentially tied (Jacobs 42 percent, Braley 41 percent), with more upside than for Jacobs because of the Democrat’s higher name recognition.

I agree with the Republicans who claimed that Jacobs’ higher name recognition and GOP support is merely a function of his heavy spending on paid advertising. He should be polling better after two months of radio and television while his opponents’ campaigns are dark. On the other hand, who’s going to stop him if his GOP rivals lack the resources to get their message out before June?