Sen. Tom Carper (D-Del.) is predicting a solid primary win for Rep. Mike Castle (R-Del.) in his Senate primary with Tea-Party backed challenger Christine O'Donnell.

Carper, a two-term former governor and five-term House member before his 2000 election to the Senate, dismissed the possibility of a close contest between Castle and O'Donnell, which has gotten harsh in recent days as O'Donnell and Castle have sharpened their attacks on each other.

O'Donnell also has the backing of former Alaska Gov. Sarah Palin (R), while Castle has the support of national Republican leaders as well as the state GOP."It's hard to imagine the Republicans turning their back on Mike Castle," Carper said.

"The conventional wisdom I see is based upon whose feelings are the most intense — the mainstream Republicans, the progressive Republicans, or the right-wing base of the party. If the right-wing base comes out in large numbers, who knows what will happen? I think Castle is likely to win by under 15 points, maybe under 10 points. But I'm not going to bet my paycheck on it."