WILMINGTON, Del. — Tea Party-backed Senate candidate Christine O'Donnell laid into her opponent, as well as the Delaware and national Republican Party, Sunday night for running "a negative and nasty campaign" against her.

O'Donnell, who faces Rep. Mike Castle (R-Del.) in Tuesday's Republican Senate primary, is facing a withering last-minute assault from Castle and the state party.


After laying low for most of the day Sunday — O'Donnell worked the church circuit and attended a handful of "private" events with supporters — the candidate huddled with her campaign manager and about 20 staffers at a local Wilmington eatery, where she spoke to The Hill.

"My opponent knows this race has serious national implications, and they're scared," O'Donnell said. "They went too negative too quickly. That's what I've been hearing from voters all day today."

Unlike Sen. Lisa MurkowskiLisa Ann MurkowskiBipartisan Senate group discusses changes to election law There is a bipartisan path forward on election and voter protections Trump sold off the Arctic Refuge — Congress must end this risky boondoggle MORE (R-Alaska), who was shocked by Tea Party-backed Joe Miller's win in that state's Republican primary, Castle has used his financial edge to attemp to define O'Donnell, running TV and radio ads hitting her on everything from her tax issues to unsettled debt from prior campaigns.

The state Republican Party also has hammered O'Donnell constantly for the past two weeks, with party Chairman Tom Ross calling her unelectable.

It's turned Delaware's Senate contest into one of the nastiest of the primary season so far, and created a dynamic unseen in previous contested primaries this cycle, in which the party establishment in the state has taken the leading role in openly slamming the Tea Party-backed candidate.

Earlier Sunday, Castle aimed his fire at the Tea Party Express, bemoaning the out-of-state influence on the primary.

"This is the first election I can remember in Delaware where a campaign is being funded almost entirely by out-of-state interests," said Castle.

O'Donnell, who has been aided by some $300,000 in spending from the Tea Party Express, has focused on Castle's "liberal" voting record in Congress and wondered Sunday how the national party could back him.

"They're throwing down the sledgehammer for a guy who doesn't even vote Republican," O'Donnell said of the National Republican Senatorial Committee. "It's appalling."

O'Donnell, who appeared upbeat and confident Sunday, was abuzz about the impending release of a Public Policy poll showing her in a dead heat with Castle. The poll also found O'Donnell with a 62-31 percent lead among self-identified conservatives.

The bad news from those numbers — pollster Tom Jensen's conclusion that should O'Donnell beat Castle on Tuesday, "it would be the best electoral news for Democrats since November of 2008."

Castle has expressed confidence he'll prevail in the primary.

"There's no question [O'Donnell] is going to have a motivated group of supporters," he told The Hill. "But I'm confident that we'll have a good turnout."

The core of staff and volunteers flanking O'Donnell on Sunday night was a devoted group. O'Donnell's volunteer coordinator said to her, the effort feels like "more of a cause than a campaign."

Included among the group was O'Donnell's campaign treasurer, Sandi Taylor, whose brother is Doug Hoffman, the Tea Party-backed candidate who fell short in a special congressional election last year. O'Donnell's campaign manager, Matt Moran, is also a Hoffman holdover, having led his bid last year.

Still, for all the trashing of the state and national GOP, O'Donnell said she has no doubt they will get behind her campaign should she win Tuesday. The party originally backed Murkowski in Alaska, but supported Miller after his primary win.

Asked whether she thought Castle would be willing to wage a write-in bid in November should he lose the primary to O'Donnell — "I absolutely think he'd do that," she said immediately.

Moran and another O'Donnell staffer quickly added that they don't think that's a possibility and said it was premature to talk about.

She also responded to a story released Sunday from the conservative magazine The Weekly Standard, which reported more details of a lawsuit O'Donnell launched against the Intercollegiate Studies Institute, a Delaware-based conservative think tank.

O'Donnell alleged gender discrimination against the think tank and sued for wrongful termination. She dropped the lawsuit in 2008, but according to court documents obtained by the magazine, she sought more than $6 million in damages and claimed "extreme emotional harm" in the complaint.

"Oh, boy," exclaimed O'Donnell when asked about it Sunday.

Legally, said Moran, his understanding is that neither party is supposed to be talking about the case.

"But I choose not to talk about it," O'Donnell said. "And shame on my opponents for bringing it up."

O'Donnell is set to make the rounds on cable news Monday, starting on Fox News around 9:30 a.m.