Former First Lady Christie Vilsack released a statement today confirming that she will not challenge Senator Chuck Grassley next year. Excerpt:

Commiting to a campaign for the US Senate next year requires more than the confidence that I have the right experience, the necessary support and the resources to be successful. It must come with an understanding that it is the best way for me serve our State and my fellow Iowans in the most effective way possible at this time. I have decided not to run for the United States Senate in 2010. I will continue my work with the Iowa Initiative to Prevent Unintended Pregnancy and will be active in our Party and across the state in issues that affect the quality of life for all Iowans. […]

While I will not be a candidate for office in 2010, never doubt I am committed to a life of service and to Iowa.

So, the mystery challenger Iowa Democratic Party chair Michael Kiernan promised for Grassley is almost certainly Roxanne Conlin, who has said she’s leaning toward running.

I wouldn’t be surprised to see former Governor Tom Vilsack run for the U.S. Senate in the future. I expect Christie Vilsack to run for Congress when Leonard Boswell’s seat (IA-03) becomes open.

Speaking of Boswell’s district, I saw at Iowa Independent that CQ Politics is calling it a “safe Democratic” seat in the House.

According to Bleeding Heartland user mirage, State Senator Brad Zaun is planning to run against Boswell next year. (I am trying to confirm that rumor.) Zaun was mayor of Urbandale, a heavily Republican suburb of Des Moines, before getting elected to represent Iowa Senate district 32 in 2004. He was re-elected to a four-year term in 2008, so he wouldn’t risk losing his seat in the upper chamber by running against Boswell.

UPDATE: Kiernan approached Conlin way back in January about running against Grassley.