Oregon's Gordon Smith has become the fourth Republican Senator to disavow John McCain's robocalls linking Barack Obama to Bill Ayers.

In a statement to the Huffington Post, Smith for Senate press secretary Lindsay Gilbride said:
"They [the Ayers calls] are not taking place in Oregon and Senator Smith does not condone these sort of calls. Negative robocalls are not appropriate and have no place in campaigns."

The McCain campaign's tactics have come under heavy fire in recent days,...