Sarah Palin Endorses Christine O'Donnell in Delaware Republican Senate Primary

WASHINGTON, Sept. 9, 2010— -- Former Alaska Gov. Sarah Palin today added Delaware's Christine O'Donnell to her pack of "mama grizzlies," hoping to give the Tea Party-backed senate candidate a final push in her bid for the GOP nomination.

"Please support Christine O'Donnell in Delaware," Palin wrote in a post on her Facebook page Thursday afternoon. "She will support efforts for America's energy security, patient-centered health care reform, cutting government waste and letting the private sector thrive and prosper!"

O'Donnell, who faces the veteran Rep. Mike Castle, has appeared to struggle in the polls ahead of Tuesday's vote. But Palin's endorsement could give her a boost – just as it has for a number of candidates across the country so far this election season.

Castle, a nine-term congressman and former governor, is flush with campaign cash, enjoys support from state and national Republican groups and has been riding a tidal wave of national public opinion swinging in his favor.

But appearances can be deceiving, especially when the Tea Party Express throws its weight behind a primary challenger. The case of felled Alaska Sen. Lisa Murkowski showed that last month.

The group has pledged $250,000 to help campaign for O'Donnell so far, airing its first ad last week that cast O'Donnell as the more conservative candidate and Castle as "one of the most liberal Republicans in Congress." But it's unclear whether they will ante up as much as $600,000 as they did in Alaska to help Joe Miller get across the finish line.

The race will be the last big primary test for the Tea Party movement, which has tried to knock off establishment Republicans who are trying to keep their jobs.

Castle voted against the Recovery Act and the Democrats' health care law, but he supported the 2008 bank bailout, cap-and-trade environmental legislation and a Democratic campaign-finance measure known as the Disclose Act. He also voted for the state fiscal aid bill last month.

A Tea Party Express poll of likely Republican voters last week showed O'Donnell and Castle in a dead heat.

But sources familiar with the Castle campaign say he has been prepared for the challenge in the wake of Murkowski's defeat, and adopted a strategy that can win.

"Tuesday's primary will be decided by grassroots Republican voters here in Delaware, not out-of-state interest groups who are working to control the outcome," Castle spokeswoman Kate Dickens told The Associated Press.

"I hear that Congressman Castle is not ignoring his opponent and has paid a lot of attention to what has happened this spring and is modeling his primary campaign after John McCain's primary campaign," Senate Minority Leader Mitch McConnell told ABC News' "Top Line" last week. "And I anticipate people [who do that will] have a better result."With help from state and national Republican groups, the Castle campaign has gone on the offensive, raising allegations that O'Donnell faced home foreclosure, owed back taxes to the IRS and took 12 years to receive her college degree from Fairleigh Dickinson University because she didn't pay her tuition.

A Castle radio ad calls O'Donnell "a financial disaster."

O'Donnell has largely denied the claims and accused Castle of employing "goons" to play dirty politics.