Dubuque-based Loras College released its second poll of the Republican primary in Iowa’s third Congressional district this week. Full results are here (pdf), toplines here. Half of the 300 likely GOP primary voters surveyed on May 14 are still undecided. State Senator Brad Zaun leads the field with 17.4 percent support, followed by Robert Cramer (8.3 percent), David Young (8.0 percent), Matt Schultz (7.6 percent), Monte Shaw (5.3 percent), and Joe Grandanette (2.0 percent).

The first Loras poll of this race had very similar results. As Bleeding Heartland discussed here, I think it’s a big methodological problem to include only self-identified Republicans in the poll sample. There are sure to be many independents and even some Democrats changing their registration on June 3 to vote in the GOP primary, because that’s where almost all the action is in Iowa this spring. Still, the poll conforms to the rumor around town that many Republicans are still undecided, and no one has broken away from the pack in the six-way IA-03 primary.

To my knowledge, Zaun and Grandanette are the only candidates not running any paid radio or television commercials. From that perspective, Zaun is fortunate that none of his better-funded rivals have overtaken him. On the other hand, being only a little ahead of the others is not a good sign for the 2010 GOP nominee in this Congressional district. I expect the convention delegates who will likely choose the nominee will look to someone else. From where I’m sitting, Shaw has the inside track in a convention scenario, as he has the most longstanding connections with Iowa GOP activists and the least baggage. But to have a shot at the nomination, Shaw probably needs to finish not too far behind the top vote-getters on June 3.