A new Susquehanna Polling & Research survey gives Delaware Attorney General Beau Biden (D) a 5-point lead over Rep. Mike Castle (R) in a hypothetical Senate matchup, news that has to relieve Democrats worried about a dubious trifecta in 2010.

General Election Matchup
Biden (D) 45 (+11 vs. last poll, 4/09)
Castle (R) 40 (-15)
Und 8 (unch)

Castle leads by 2.3 points in the RCP Average of Delaware Senate polling.

In this poll, Castle performs slightly better among Republicans than Biden does among Democrats, and holds a 5-point lead among independents. The problem for the state's lone Congressman and former governor is that there are 106,000 more registered Democrats than Republicans in the First State.

Susquehanna also attributes Castle's slippage to "negative publicity he received in the state after casting a 'no' vote for President Obama's health care bill in the U.S. Congress." That vote occurred just over 48 hours before the poll went into the field.

This survey of 850 registered voters was conducted November 10-15, and has a margin of error of +/- 3.36 percent.