Representative Bruce Braley and State Senator Joni Ernst face off today for the first of three scheduled debates. You can watch at 5 pm on C-SPAN or on KCCI-TV if you live in the Des Moines viewing area. KCCI and the Des Moines Register will live-stream the debate as well.

Debates rarely change election outcomes, but they are high-stakes events because a mistake provides fodder for a wave of attack ads. Republicans have been bashing Staci Appel for two weeks already over one awkward response she gave during her Congressional candidate debate with David Young.

Follow me after the jump for a preview of the major risks for each candidate in the IA-Sen debate. Braley goes in under more pressure after the latest Des Moines Register Iowa poll showed him behind by 6 points. But the format creates some potential pitfalls for Ernst too.

By the way, in her ongoing quest to displace WHO-TV’s Dave Price as the favorite journalist of central Iowa Republicans, the Des Moines Register’s Jennifer Jacobs put her thumb on the scale in her debate preview. Jacobs attributes negative views of Braley to “voters” while dismissing criticism of Ernst as coming from “Democrats.” Memo to Register publisher Rick Green: we know you’re conservative, but it’s embarrassing for your chief political reporter to express such a clear preference ahead of a debate your newspaper is co-sponsoring. Maybe you should move Jacobs over to the opinion page during your upcoming job shuffle.

Risks for Braley

Being too aggressive. Braley’s career as a trial lawyer has come through in his past debates, in good and bad ways. He dismantled Republican challenger Ben Lange in the 2012 candidates’ radio debate. It worked partly because Lange is an ambitious attorney himself, with an attack-dog style. If Braley approaches his debate with Ernst in the same way, he will be accused of bullying and disrespecting a woman.

I’m aware that no matter what happens today, the Ernst rapid response team will shout in all available media formats that Braley was rude, arrogant, elitist, and condescending. While he can’t prevent that from happening, he shouldn’t provide unnecessary ammunition for their talking points.

Looking angry. Braley’s been a fairly effective member of Congress for the last eight years, with real accomplishments for his district and in federal policy more broadly. He grew up close to grandparents who farmed, and even spent time working on their farm. Yet for many Iowans, millions of dollars in outside spending has defined Braley as a guy who hates on farmers and doesn’t show up for work. His campaign keeps trying to redirect the conversation toward issues such as Ernst’s stand on the minimum wage, Social Security, and access to abortion and birth control. Nevertheless, the prevailing media coverage of this race repeatedly falls back on Braley’s “gaffes” and Ernst’s appealing personal qualities. He must be furious.

Braley let Lange get under his skin during the candidates’ second debate in 2012. Ernst’s team has probably prepped her with some lines intended to provoke a similar reaction today. Braley cannot afford to look angry and frustrated during Iowans’ first opportunity to see the candidates side by side. Ernst regulates her emotions well and will not fly off the handle.

Risks for Ernst

Looking uninformed. Even her allies would concede privately that Ernst has had some shaky moments when she talks about public policy in an unscripted setting. That includes some of the debates and candidate forums during the GOP primary, as well as some newspaper interviews. She isn’t as familiar with federal government policies as Braley. Her supporters make that a virtue (“not a career politician”), but she needs to demonstrate a basic knowledge of the work she would be doing in the Senate.

Since this debate is only an hour long, and I don’t expect any oddball questions from the panel, Ernst has presumably been able to rehearse all the answers she’ll need. But watch out if she gets knocked off her talking points. That happened a few times during the IA-Sen GOP primary debate that KCCI hosted in May. For instance, moderator Kevin Cooney asked all the candidates to name three federal policies they’d like to repeal. He specifically asked them not to mention Obamacare, since “we know you’re all against Obamacare.” Ernst said Dodd-Frank (the 2010 financial reform law), “many, many” rules from the EPA (when pressed for an example she said the Clean Water Act), and finally, Obamacare–even though Cooney had asked them all not to include that law. It gave the impression that she doesn’t know the facts to back up her talk about job-killing regulations.

Sounding like she’s reciting a script. Ernst has had months to prepare for this debate. Rehearsing is good, but sometimes during the Republican primary campaign, she came across as programmed in her delivery. She has a facial expression that’s hard to describe but doesn’t look like a person simply responding to a question. Rather, she can convey a sense of trying to remember what she’s supposed to say about this or that. While Ernst needs to stick reasonably close to her talking points, she should try to sound like she’s speaking naturally, not from a memorized list of answers.

Any comments about the IA-Sen race are welcome in this thread. I’ll post a live-blog and discussion thread soon.