WILMINGTON, Del. -- If there was a lesson to be learned in the wake of Alaska's Republican Senate primary, Rep. Mike Castle's (R-Del.) campaign appears to have learned it.
Campaigning in Wilmington ahead of Tuesday's primary where Tea Party-backed Christine O'Donnell is riding some last-minute momentum courtesy of endorsements from former Alaska Gov. Sarah Palin and Sen. Jim DeMint (R-S.C.), the longtime congressman told The Hill he's taking nothing for granted.
Castle said Sen. Lisa Murkowski (R-Alaska) phoned him after her stunning primary loss at the hands of Tea Party-backed Joe Miller with a warning.
"She told me to be careful, because [The Tea Party Express] will come at me with everything they've got," Castle recounted. "They're certainly not above misrepresentation."
Castle said while he took Murkowski's warning to heart, he was already taking the primary challenge from O'Donnell seriously.
"We understand what we're up against and we're not taking this lightly," Castle said, bemoaning the involvement of the Tea Party Express. "This is the first election I can remember in Delaware where a campaign is being funded almost entirely by out of state interests."
The Tea Party Express has spent close to $300,000 running radio and TV ads in support of O'Donnell.
Unlike Murkowski in Alaska, the Castle campaign has spent heavily on ads hitting O'Donnell's record before the primary. Castle is on the air in the costly Philadelphia market ahead of Tuesday with an ad highlighting O'Donnell's finances and tax record.
Greeting voters Sunday at the Brandywine Arts Festival in downtown Wilmington, Castle acknowledged the challenge of ensuring that his supporters come out in Tuesday's closed Republican primary, which clearly has conservatives motivated.
"There's no question [O'Donnell] is going to have a motivated group of supporters," he said. "But I'm confident that we'll have a good turnout."
Castle is set to watch Sunday's Philadelphia Eagles game at a local restaurant later this afternoon, but his early choice of venue Sunday seemed a bit curious.
Voters here greeted Castle like an old friend, with most calling him by his first name and offering him encouragement ahead of Tuesday, but it was tough to find Republicans in the Arts Festival crowd.
There were plenty of Democrats familiar with the primary battle on the Republican side, though.
"It would be frightening," said Jeff Turi of Alapocas, Del. on the prospect of an O'Donnell victory Tuesday. Turi is a registered Democrat. "It would show just how extreme the Republican Party has become. But I don't think she has a shot."