He'll likely face Beau Biden for the seat vacated by his father, Vice President Joe Biden, this year. Biden, the younger, returned from Iraq in late September, and was planning to make a decision about his political future shortly.
Castle's presence in the race could complicate that decision although one Democratic source said Tuesday that he still "fully expects Biden to run". Castle's candidacy is a major recruiting victory for the National Republican Senatorial Committee, which had been aggressively courting the Delaware GOPer for months.
As Mike Allen noted in this morning's Playbook, Delaware leans Dem, but Castle is tough there. The Rothenberg Political Report has moved Delaware's Senate race from "Currently Safe for Democrats" to "Lean GOP Takeover." Having trouble finding video just yet, but Mike Memoli of Real Clear Politics tweeted some of Castle's comments:
Castle says he expects to be running against Beau Biden. Talks up friendship with VP Biden Castle: "When you deal with any of the Bidens, you deal with all of the Bidens." Says he wants campaign DE "can be proud of" Castle said he decided more than a week ago, wanted to wait until Biden was back from Iraq.
More quotes from the news conference at DelawareOnline, where Delaware denizens are voting on the possible match-up. Castle is winning the utterly unscientific poll. Castle's campaign web site, launched today, is here.