Seven-term Democratic incumbent Leonard Boswell always has a target on his back. He has failed to top the 56 percent mark in any election this decade, but he has cobbled together the right coalitions to win each of those elections.

Republicans, though, point to the fact that he only won with 52 percent of the vote in 2006, which was a Democratic "wave" year, as a sign of extreme vulnerability this election cycle--which all signs point to being an equally strong GOP wave year. Boswell will be in for another nail-biter this election cycle, as he faces off against Republican challenger Brad Zaun, a state senator and former mayor of Urbandale.

Boswell is defending the only district in Iowa that does not share a border with another state. Fittingly, Zaun and Boswell have painted each other as being unresponsive to the issues specific to the district. Zaun has attacked Boswell for swinging to the left and becoming more liberal than the district's constituency, citing Boswell's support of Obama's agenda, including financial regulation, cap-and-trade, and health care reform.

Boswell, meanwhile, repeatedly has brought up Zaun's prior position against ethanol subsidies, which Zaun took to curry favor with the Tea Party activists who helped him gain the GOP nomination. In recent weeks, Zaun has told reporters that, after "rethinking the issue, he now supports ethanol subsides. That hasn't stopped Boswell from going on the radio to attack Zaun for his flip-flop, questioning whether he would provide a reliable vote on an issue that is dear to voters of this district and state.

And then there is this: the Des Moines Register unearthed a police report from 2001 in which Zaun allegedly harassed a former girlfriend. Zaun has not denied that the incident occurred, and the more it is brought up, the more it may hurt Zaun with female voters.

Polls are all over the place, with both candidates pointing to surveys that have them slightly ahead. A debate between Boswell and Zaun will be held on October 25. One sure thing, however, is Boswell's significant fundraising advantage. He also has the backing of national Democrats who will help him flood the airwaves as election night approaches.

Bottom line: This race seems to encapsulate the mood of this election cycle. A Democratic incumbent is vulnerable, but he is claiming that the GOP candidate will do more harm than good and will not bring home the bacon, so to speak, especially concerning ethanol. The anti-appropriation mood may be so strong that voters in other states may elect candidates who threaten to cut local projects and subsidies. But this outcome is less likely in Iowa.

But if there is a strong GOP wave on the horizon, Boswell may be in trouble, as this race has gone from "lean Boswell" to "toss-up" in recent weeks.  

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