Vice President Joe Biden's former Senate seat is more likely to stay in Democratic hands after the victory of Christine O'Donnell in the Republican primary Tuesday.

The Ballot Box has shifted the Delaware Senate race from "leans Republican" to "leans Democratic."

Republicans had been hopeful of capturing the seat with centrist Rep. Mike Castle (R-Del.) as the party's nominee. O'Donnell's bid is far more problematic for the GOP.

She is a perennial candidate who has made several unsuccessful runs for office. O'Donnell has been a frequent guest on television and radio shows to advocate for abstinence and other social issues, which won't win centrists or Democrats in Delaware. In 2008, she said then-Sen. Barack Obama was "anti-American."

A Public Policy Polling survey out Wednesday shows Democrat Chris Coons enters the general election race with a 50-34 lead over O'Donnell. Had Castle won Tuesday night, he would have a 45-35 lead over Coons, according to the Democratic firm's Sept. 11-12 poll of 958 likely Delaware voters.

O'Donnell has the support of Sarah Palin and Sen. Jim DeMint (R-S.C.), and the national party appears willing to support her.

"I reached out to Christine this morning, and as I have conveyed to all of our nominees, I offered her my personal congratulations and let her know that she has our support," Sen. John Cornyn (Texas), chairman of the National Republican Senatorial Committee, said in a statement  Wednesday. "This support includes a check for $42,000 — the maximum allowable donation that we have provided to all of our nominees — which the NRSC will send to her campaign today."

She certainly needs the money — O'Donnell had only $20,000 banked at the end of August. Coons has almost $1 million.

See the Ballot Box's complete race ratings here.