A new Public Policy Polling (D) survey in Delaware gives Rep. Mike Castle (R) a 6-point lead over Attorney General Beau Biden (D) in the 2010 special election to fill Vice President Biden's unexpired term. That is only slightly changed from a March survey also showing Castle ahead.

General Election Matchup
Castle 45 (+1 vs. last poll, 3/5-8)
Biden 39 (+3)
Und 16 (-4)

Castle leads by 1.7 in the RCP Average for the race.

Castle has a stronger favorable rating -- 55/28 -- than Biden -- 43/35. Castle, an established moderate Republican who has won a dozen statewide races in Delaware, also has a stronger hold on his own base with 79 percent of the Republican vote, compared to Biden's 65 percent draw among Democrats. Castle leads among independent voters 52-23 percent. Asked about his ideology, 19 percent of Delawareans say Castle is too liberal, 26 percent say he's too conservative, and 55 percent say he's "just right."

"Mike Castle has more appeal to Democrats and independents than any other Republican Senate candidate in the country and that's allowing him to hold the early lead in this race," said PPP's Dean Debnam.

President Obama's approval rating in the state is down to 53 percent, while 41 percent approve. The survey was conducted November 30-December 2 among 571 registered voters, and has a margin of error of +/- 4.1%.