Not long after the 2004 election, Pederson's name began being mentioned as a potential Senate candidate for the 2006 race. On July 28, 2005, Pederson formally stepped down as Chairman of the Arizona Democratic Party, further fueling those speculations. In early September 2005, an e-mail was sent from the Arizona Democratic Party's website, inviting people to an announcement by Pederson on September 7. In an anticlimactic move, an e-mail was sent out shortly after the first saying that the announcement would be postponed due to Hurricane Katrina. It was requested that any money that would be donated to Pederson's campaign at the announcement be directed to relief efforts instead. Similarly, a meeting in Arizona of the Democratic National Committee (DNC) was scheduled for around the same time. It was also postponed and the same request was made involving donations. On September 7, 2005, Pederson filed to run for the U.S. Senate. On September 14, 2005, Pederson formally announced his intention to run, in his hometown of Casa Grande, Arizona.